Picadillo usually (recipes vary widely) consists of meat with pimentos, olives, and raisins, served over rice. The Spanish recipe has found its way from Cuba and Mexico to the Southwestern U.S.
 
 
Wikipedia: Picadillo
Picadillo is a dish mainly consisting of ground beef typically found in Cuba, Mexico, and other Latin American countries. It is normally used as a filling, such as for tacos, and can be mixed with vegetables. The name comes from the Spanish word, “picar” which means “to prick”.

Picadillo is a traditional dish in many Latin American countries; it’s made with ground meat, tomatoes, and regional ingredients. The Cuban version includes olives and is usually served with black beans and rice.

Tex-Mex Recipes
Picadillo recipe
Recipe ingredients
1-1/2 lbs. lean ground beef
1 large onion, chopped
2 large fresh tomatoes, peeled and chopped or one 14-1/2 oz. can whole tomatoes, chopped
2 large garlic cloves, crushed
2 medium potatoes, cut into 1/2” dice
1/2 cup beef stock, chicken stock or water
2 teaspoon apple cider vinegar
1 canned chipolte chile with 1/2 teaspoon adobo sauce
1/4 teaspoon ground cumin
1/2 teaspoon salt
1 teaspoon minced fresh cilantro
Recipe method
Over medium heat, brown the ground beef with the onion and garlic.
Drain accumulated meat juices and add remaining ingredients except cilantro.
Simmer over medium-low heat for about 20 to 25 minutes, stirring occasionally.
Do not let mixture get too dry. Add a tablespoon or so of water or stock, if necessary.
Serve warm, sprinkled with cilantro.
 
(Oxford English Dictionary)
picadillo, n.
Cookery.
[< Spanish picadillo hash, minced meat (1606 or earlier in this sense) <

picado (adjective) minced (late 14th cent. or earlier; use as adjective of past participle of picar to grind, to mince (13th cent. or earlier in this sense; a1207 in sense ‘to pierce, wound with a sharp object’: see PICK v.1)) + -illo, diminutive suffix (cf. -ILLUS suffix).] 
Any of various dishes of Spanish or Latin American origin, made with ground or minced meat; spec. a spiced hash, popular in Central America and Cuba, typically made with peppers and other vegetables. Also used as a filling.

1877 MRS. F. LESLIE California xi. 120 The German finds his sauerkraut, the Italian his maccaroni, the Spaniard his picadillo, and the Welshman his leek, each at his own house of refreshment.
1946 Hispania 29 224 The main dish at the White House luncheon on April 20 was picadillo, followed by a green salad, guayaba paste and New Mexican cheese, and coffee, Cuban style.
1969 Daily Gleaner (Kingston, Jamaica) 16 Oct. 19/3, I make Piccadillo in double batches, as it freezes well.
2003 Time Out N.Y. 11 Sept. 54/2 Stunning regional dishes like fire-roasted poblano chilies stuffed with organic roasted-turkey picadillo.
   
13 May 1926, Kingsport (TN) Times, pg. 6, col. 1:
Filling for Enchiladas (Picadillo)
1 pound pork
1 tablespoon shortening
1 teaspoon chopped onion
Clove of garlic (chopped)
1/2 cup chili sauce
1 tablespoon chopped green olives
1 tablespoon chopped, blanched almonds
1 tablespoon raisins (chopped)
1 teaspoon vinegar
1 pinch salt
1 pinch sugar
1 teaspoon olive oil
Boil pork until tender, then chop fine. Melt shortening and fry pork until brown. Add onion, garlic, and chili sauce, and fry for three minutes. Add olives, almonds, and raisins, and cook two or more minutes. Just before removing a vinegar, salt, sugar and olive oil
 
10 April 1946, Lincoln (NE) State Journal, “Mrs. Truman, hostess, will help in white house kitchen,” pg. 6, col. 3:
The main dish will be picadillo, consisting of rice, beef, pork, and lamb generously garnished with almonds, pimento, olives, raisins and hot spices, a recipe composed by the professor.
 
9 January 1959, Chicago (IL) Daily Tribune, pg. A5:
Picadillo Is Hamburger in Spanish
Picadillo is the Spanish version of hamburger, and it’s a quickly made supper dish the whole family will go for. Make it as follows:
 
PICADILLO
[Four servings]
1 medium onion, chopped fine
1 medium green pepper, diced
1 small can pimentos, drained and diced
1/4 cup Spanish olive oil
1 pound chopped beef
Hot cooked rice

Cook onions, green pepper, and pimentos in olive oil until onion is tender. Add beef and stir once or twice with a fork until meat is cooked. Serve over hot cooked rice.
   
16 April 1959, Dallas (TX) Morning News, section 5, pg. 18:
(From “Elena’s Secrets of Mexican Cooking”—ed.)
PICADILLO
This filling can be used for tamales, tacos, enchiladas or used with the white rice recipe above, and baked in a casserole in a 350 F. oven for 30 minutes.
 
One pound lean ground beef or pork, 1 onion chopped, 3 tablespoons oil (omit when using pork), 2 tomatoes, or 1 cup solid pack canned tomatoes, 1 tablespoons vinegar, 1 teaspoon sugar, 1 teaspoon cinnamon, pinch of ground cloves, 1/4 teaspoon ground cumin seed (optional), 1 teaspoon salt, 1/4 cup raisins plumped in 1/4 cup hot stock or water, peeled green chiles or chile powder, 1/2 cup slivered blanched almonds.
 
Brown meat and onion in heated oil. Add all other ingredients except almonds. Stir to blend. Bring to a boil, reduce heat and simmer for 30 to 45 minutes. Stir in almonds. THis freezes well.
 
If you want to make a casserole of this meat hash and the white rice, use it in layers, in a casserole, starting with the rice. Bake in a 350 F. oven for 20 minutes, and serve with guacamole salad.
 
19 October 1967, Galveston (TX) Daily News, pg. 12A ad:
MEXICAN BUFFET
(...)
Green Picadillo
 
10 June 1972, Chicago (IL) Tribune, “Picadillo: A Spanish Hash” by Mary Meade,  pg. NB24:
PICADILLO is a sort of Spanish hash, generally consisting of ground beef cooked with tomatoes, onion, garlic, capers, raisins, and pimento-stuffed olives. It is a thrifty dish which stretches meat further. It’s also a tasty dish with a pleasing flavor contrast between sweet raisins and tangy olives. Mexico has its own version of picadillo too, and frequently in that country, it is used as a filling for tamales, empanadas, tacos, enchiladas, and the like. Your family will enjoy this exotic hash as a stuffing for green peppers.