Tortillas Stuffed with Cheese (Quesadillas)

For the filling: combine all ingredients except the shortening, cheese, tortillas, onion, and avocados, and sauté in about a tablespoon of shortening. Let simmer until thickened. Cook the mixture and add the cheese. Mix well. Heat tortillas to soften them and put a generous dab the filling on each one. Fold over once, fasten with toothpicks, and fry in deep hot shortening until Golden Brown. Garnish with minced onion and avocado slices.