Tostones Rellenos (Stuffed Plantain Cups)

Step 1
Heat oil in a deep fryer or large saucepan to 350 degrees F (175 degrees C).

Step 2
Fry plantains in hot oil until golden but not brown, 5 to 7 minutes. Smash each piece of plantain in a tostonera or with the bottom of a small dish to make a small disk, then shape each disk into a small cup. Fry cups in hot oil until golden and crisp, 5 to 7 minutes more. Drain on a paper towel-lined plate, season with garlic salt, and set aside.

Step 3
Preheat the oven to 350 degrees F (175 degrees C).

Step 4
Make filling: Heat a large skillet over medium-high heat. Add ground beef to the skillet; season with salt. Cook and stir until beef is crumbly and browned, about 10 minutes. Drain and discard any excess grease. Stir sofrito, tomato sauce, water, saz?n seasoning, and olives into beef. Reduce heat to medium-low and simmer until liquid is reduced, about 15 minutes.

Step 5
Fill plantain cups with beef mixture, top with Cheddar cheese, and arrange on a baking sheet.

Step 6
Bake in the preheated oven until cheese is melted, 5 to 8 minutes.