A highly seasoned mixture of lightly fried vegetables and spices, sofrito is at the heart of many Caribbean, Latin American, and Spanish dishes, from beans and rice to meat and fish (see Sofrito Scallops with Saffron Rice).
Sofrito originated in medieval Catalan cuisine (sofrito comes from sofregir, a Catalan word meaning to lightly fry), and there are references to it dating back to the 1300s. Originally, it was based on onions long-cooked in olive oil or lard, but once explorers brought tomatoes back from the Americas in the 16th century, they became a standard addition. From Spain it spread to the Spanish colonies, where variations from mild to acidic to spicy still exist. In the Dominican Republic, the sofrito, also known as sazón, is balanced with vinegar for more acidity and annatto seeds for color. In Puerto Rico (where it's called recaísto) and Cuba, sofrito contains onion, bell peppers, garlic, tomatoes, and cilantro.