The “blintze” (or “blintz,” usually plural as “blintzes,” a diminutive from the Russian “blin” for pancake or crêpe) was served on the Jewish Lower East Side of Manhattan by at least 1900. Ratner’s restaurant on Delancey Street (1905-2002) served blintzes (cheese, potato, cherry, prune, apple and other fillings) with sour cream and became almost an institution, also selling blintzes to the frozen foods sections of supermarkets.
 
“Blinis” are cited in English in the Russian cuisine from at least the early 1800s.
   
   
Wikipedia: Blintz
A blintz, blintze or blin (plural: blintzes, Lithuanian: Blynai, blynai; Russian: блин blin, блины (pl.) Polish: bliny; Ukrainian: млинці, mlyntsi; Yiddish: בלינצע blintze) is a thin pancake (similar to a crêpe).
 
Etymology, origins, culture
The English word blintz comes from the Yiddish בלינצע (“blintze”), which in turn comes from blin. “Blin” comes from Old Slavic mlin, that means “to mill” (compare the Ukrainian word for blin млинець, mlynets’).

Blins had a somewhat ritual significance for early Slavic peoples in pre-Christian times since they were a symbol of the sun, due to their round form. They were traditionally prepared at the end of the winter to honor the rebirth of the new sun (Pancake week, or Maslenitsa). This tradition was adopted by the Orthodox church and is carried on to the present day. Bliny were once also served at wakes, to commemorate the recently deceased.

Traditional Russian bliny are made with yeasted batter, which is left to rise and then diluted with cold or boiling (zavarnye bliny) water or milk just before baking them in the traditional Russian oven (to this day the process of cooking bliny is referred to as baking in Russian, even though these days they are almost universally pan-fried, like pancakes). By Russian tradition the first blin is always destroyed while frying. Blintzes (blinchiki in Russian, considered to be a borrowed dish) are made from unyeasted batter (usually made of flour, milk and eggs) and are nearly identical to French crêpes. All kinds of flour may be used for making bliny: from wheat and buckwheat to oatmeal and millet, although wheat is currently by far the most popular.
 
Blintzes were popularized in the United States by Jewish immigrants who used them in Jewish cuisine. While not part of any specific religious rite in Judaism, blintzes that are stuffed with a cheese filling and then fried in oil are served on holidays such as Chanukah (as oil played a pivotal role in the miracle of the Chanukah story) and Shavuot (when dairy dishes are traditionally served).
 
Blins may be prepared and served in three basic ways.
 
. They may be eaten “as is”. In this case the batter may contain various add-ins, from grated potato or apple to raisins. These blini are quite common in Eastern Europe and are more solidly-filled than the spongy pancakes usually eaten in North America.
. They may be smeared with butter, sour cream, jam, honey, or caviar (whitefish or salmon caviar, traditional sturgeon caviar is not kosher) and possibly folded or rolled into a tube. In that form they are similar to French crêpes. The caviar filling is popular during Russian-style cocktail parties.
. (The term “blintz” is mostly applicable to this version): A filling such as jam, fruit, potato, cottage cheese or other cheese, cooked ground meat, cooked chicken and even chopped mushrooms, bean sprouts, cabbage and onions (for a Chinese eggroll-type blintz) is rolled or enveloped into a pre-fried blintz and then the blintz is lightly re-fried, sautéed or baked. Such a blintz is also called nalysnyky in that form (Ukrainian: налисники) or blinchiki (Russian: блинчики).
 
Buckwheat bliny are part of traditional Russian cuisine, almost forgotten during the times of the Soviet Union. They are still widespread in Ukraine where they are known as hrechanyky (Ukrainian: гречаники), and Lithuania’s Dzūkija region, the only region in the country where buckwheat is grown. It is traditionally called Lithuanian: Grikių blynai.
 
Merriam-Webster Dictionary
Main Entry: blin·tze
Pronunciation: \ˈblin(t)-sə\
Variant(s): or blintz \ˈblin(t)s\
Function: noun
Etymology: Yiddish blintse, of Slavic origin; akin to Ukrainian mlynets’, diminutive of mlyn pancake
Date: 1903
: a thin usually wheat-flour pancake folded to form a casing (as for cheese or fruit) and then sautéed or baked
 
(Oxford English Dictionary)
blin, n.
[Russ., pancake.] 
  (See quots.)
1889 Harper’s Mag. LXXVIII. 854/1 The terrible Russian General absorbs before his soup a dozen blinieswhich are heavy pancakes stuffed with caviare and seasoned with hot melted butter.
1892 T. F. GARRETT Encycl. Pract. Cookery II. 157/2 Blinis, small meal cakes which are eaten in Russia during Lent.
1920 M. W. DAVIS Open Gates to Russia xvi. 247 Bliný, the crisp Russian pancakes.
1943 E. M. ALMEDINGEN Frossia x. 376 They remembered bliny, those famous Carnival pancakes, thin and golden, eaten sometimes with sour cream, and oftener with caviare.
 
(Oxford English Dictionary)
blintze
[Yiddish blintse, f. Russ. blinets, dim. of BLIN.] 
  = BLIN.
1903 Jewish Encycl. IV. 256/1 The kasha and blintzes of the Russian Jews..are dishes adopted by the Jews from their Gentile neighbors.
1932 L. GOLDING Magnolia St. I. ii. 32 Wouldn’t it be nice to make a few blintsies for Mr. Emmanuel.
1958 W. BICKEL tr. Hering’s Dict. Class. & Mod. Cookery 10 Cheese blinzes.., crêpes au fromage á la juive.
1961 Woman 21 Jan. 16/3 Blintzes are cheese-filled pancakes served with jam.
       
Google Books
The White Slave:
Or, The Russian Peasant Girl
by Charles Frederick Henningsen
Volume II
London: Schulze and Co.
1845
Pg. 178:
And then, as if in dread that this would not be sufficient to take off the edge of their appetites, hot blinis, or pancakes, both of buckwheat and ground rice, were served at intervals, with an imitation of the Italian ravioli;...
   
La Gastronomie en Russie
par A. Petit
Chef de Cuisine de Son Excellence Monsieur le Comte Panine, Ministre de la Justice
Paris: Chez l’Auteur, 18, Rue Martel
1860
Blinis.  98
—de sarrasin.  98
—creme de riz. 101
—de gruau. 105
—au kache de sarrasin.  102
—de pommes de terre.  103
—de pommes de terre a la levure.  103
—a la semoule.  101
—aigre-doux.  104
—livoniens.  105
—a la farine de ble de Turquie.  105
—au parmesan.  106
—rouges aux carottes.  106
—aux chabots.  107
     
Season 1892-1893, St. Nicholas Hotel (Cincinnati, OH) menu (NY Historical Society menu collection), pg. 4:
Blinis of Caviar, Skobeleff
   
7 November 1900, Duluth (MN) News Tribune, “Jewish Coffee and Tea Houses,” pg. 8:
One of the distinguishing features of the East Side downtown is found in the tea and coffee houses kept by Hebrews.
(...)
The glory of these establishments, however, is the blintz, which is a sort of pancake rolled up and inclosing curds made savory. The Jews seem fond of the blintz which is cooked upon gas stoves just like buckwheat cakes, and is eaten as hot as the customer’s mouth can endure. One of the best Jewish coffee houses has a great reputation for blintzes and announces the delicacy as follows:
 
“The time has now arrived
hen you can be satisfied
by eating blintzes in this place
Two cents apiece, Ten cents the plate.”
 
The descent from poetry into mere financial prose is not as satisfying as the blintzes, which are indeed excellent.—New York Sun.
 
Chronicling America
31 May 1903, New-York (NY) Tribune, “Most Joyous of the Ancient Hebrew Holidays - Shabuoth,” pg. 7, col. 4:
But the most striking dish of the feast is the “blintze.” This dish is made of cheese, around which is rolled a delicious pancake, made of eggs, flour and butter. This is then fried, and furnishes the piece de resistance of the Shabuoth banquet.
 
August 1907, Confectioners Journal, pg. 85, col. 2:
Blinis a la Czarina.
   
Feeding America
The International Jewish Cook Book:
1600 Recipes According To The Jewish Dietary Laws With The Rules For Kashering:
The Favorite Recipes Of America, Austria, Germany, Russia, France, Poland, Roumania, Ect., Ect.
By Florence Kreisler Greenbaum
New York, NY: Bloch Pub. Co.
1919
Pg. 239:
CHEESE BLINTZES…
SWEET BLINTZES…
Pg. 240:
BLINTZES…
Pg. 387:
PRUNE BLINTZES…
MEAT BLINTZES…
 
25 March 1926, Salt Lake Tribune  (Salt Lake City, UT), “Horse Sense and Satire” by O. O. McIntyre, pg. 6, cols. 4-5:
Speaking of food, one of the most delectable dishes in Manhattan is found in jostling Hester street, the push-cart paradise. They are blintzes, a sort of fried cheese fritter. They are of Yiddish origin and a piece de resistance of the Kosher cafes.
 
7 June 1926, Oakland (CA) Tribune, pg. 8, col. 6:
Blintzes
Two eggs, 1 cup water, flour to make thin batter, butter a griddle and cover thin with batter. Cook until firm. Take off and cut into squares. Fold in Tuttle’s Cottage Cheese and fry in butter. Sprinkle with sugar and cinnamon. Serve hot.
 
18 July 1926, San Antonio (TX) Light, American Weekly, pg. 14, col. 6:
Cheese Blintzes or Fritters
Batter—1 egg, 1 cup water, 1/2 teaspoon salt, 1 cup sifted flour.
Filling—1 cup cottage cheese, 2 tablespoons butter, 1 egg, salt, sugar and cinnamon to taste, grated peel 1 lemon.
 
Have the filling mixed and a clean bread board ready on which to lay the batter when cooked. To make the batter, beat the egg very thoroughly, add the water, salt and flour, and beat all until smooth. Have a skillet hot and lay in butter. Pour about two tablespoons of the batter onto the skillet, and tilt it so the batter is as thin as possible. (Thin batter is the secret of good blintzes!) Cook over very low fire and fry on one side only, remove each “blintz” to the bread board with the uncooked side uppermost, and let cool. Spread the filling mixture on the cooled dough, fold over and tuck the edges in well like a small “envelope.” Sprinkle with powdered sugar and cinnamon and fry to a light brown on both sides in hot butter. Serve immediately.

The Pittsburgh Jewish Newspaper Project
26 December 1930, The Jewish Criterion, pg. 36, cols. 2-3:
CHEESE BLINTZES
With a fork beat up one egg, one-half teaspoon of salt, ass one cup of water and one cup of sifted flour, heat until smooth. Grease a frying-pan very slightly, our in two tablespoons of the batter, tilting the pan so as to allow the batter to run all over the pan. Fry over a low heat on one side only, turn out the semi-cooled cakes on a clean cloth with the uncooked side uppermost; let cool. Prepare a filling as for cheese kreplich, using one-half pound of potcheese, a piece of butter size on one egg, add one egg, pinch of salt, a little cinnamon and sugar to taste and grated peel of a lemon. Spread this mixture on the cooled dough, fold over and tuck the edges in well. Then sprinkle with powdered sugar and cinnamon, and fry in plenty of oil or butter. These blintzes are served hot.
 
SWEET BLINTZES
Make dough as directed for cheese blintzes. Filling may be made of force meat, highly seasoned; fry in hot fat. Filling may also be made of one-half pound of apples, peeled and cored and then mixed with one ounce of ground sweet almonds, one ounce of powdered sugar, a pinch of cinnamon, juice of one-half lemon; mix well and bind with the beaten white of egg.
 
Spread either of these mixtures on the dough, fold over and tuck edges in well. Fry in plenty of oil or fat.
 
Sprinkle those containing the fruit mixture with sugar and cinnamon. They may be served either hot or cold.
 
The Pittsburgh Jewish Newspaper Project
22 April 1932, The Jewish Criterion, pg. 85, col. 3:
Prune Blintzes
Take three cups potato flour mixed with three eggs, add a little water and mix well. Heat a small frying-pan, grease with a little fat and pour into it enough batter to make thin pancakes. Chop prunes, add a little sugar and fill each cake with this mixture. Fold into three-cornered pieces and fry. When done put in a pan, sprinkle with sugar and bake in oven. Do not let burn.
Meat Blintzes
The same pancakes can be used with meat taken from soup. Fry two small onions with a little fat and chop with the meat. Add two eggs, salt and pepper to taste.
 
Google Books
I Can Get It For Your Wholesale
by Jerome Weidman
New York, NY: Simon and Schuster
1937
Pg. 26:
“Get the gentleman another plate of blintzes.” 
 
Google Books
Tevye’s Daughters
collected stories of Sholem Aleichem
translated by Frances Butwin
New York, NY: Crown Publishers
1949
Pg. 149:
“But see to it that the blintzes are good and hot.”
     
Meet the Folks:
A Session of American-Jewish Humor
with Sammy Levenson
New York: The Citadel Press
1951
Pg. 119:
BLINTZES Dairy sleeping bags
 
New York (NY) Times
Lower East Side Journal; After Almost a Century, a Final Blintz
By ANDY NEWMAN
Published: September 30, 2002
The other latke finally dropped on Delancey Street yesterday.
 
Ratner’s Delicatessen, the Lower East Side kosher-dairy haven where rude waiters had dished out featherlight matzo balls and pucklike potato pancakes since 1905, dimmed its orange neon sign for the last time last night after years of flickering on the brink of extinction.
 
The Lansky Lounge, a swanker steak-and-seafood restaurant with the same owners which has split the space at Delancey and Norfolk Streets with Ratner’s for the past five years, will continue to expand gradually, said Robert Harmatz, whose family has owned Ratner’s since 1918.
(...)
’‘It’s the last supper, so I wanted to eat everything,’’ said Jan Greiner, of Union, N.J., after essaying the variety blintz plate, the vegetarian cutlet and the potato pancakes (or latkes), among other things.
(...)
For the sentimentally inclined, Mr. Harmatz noted that several Ratner’s staples, like the pirogen and the blintzes, have found their way onto Lansky’s menu, interspersed with the tuna sashimi and the crab crepes. And above the restaurant, Ratner’s frozen food operation continues to churn out several million dollars a year in delicacies, available in grocers’ freezers throughout the diaspora.
 
’‘Our best market is in Florida,’’ Mr. Harmatz said. His loyal customers there include Mr. Weidman’s mother, Edna, who said by phone that she bought her Ratner’s blintzes—‘’$1.99 for six!’’—in a store near her home in Coconut Creek.