For a spicier version, add a chopped jalapeño or a dash of hot sauce to the beef mixture. You can also substitute ground turkey or chicken for the beef for a lighter option. If you prefer a vegetarian version, omit the meat and add more beans or some sautéed vegetables like bell peppers and zucchini. For a creamier texture, mix in a cup of sour cream or cream cheese into the beef mixture before baking.