Puerto Rican stuffed shells or caracoles rellenos are pasta shells filled with ricotta cheese, savory ground beef, and topped with marinara sauce and mozzarella. The ground beef is seasoned with adobo and sazón and cooked in a sofrito sauce. This adds a ton of flavor to this dish. I love making this for dinner on busy weeknights as it comes together in 45 minutes or less. It also freezes well so you can make ahead and keep a stash for later use!