Source: Martha Stewart Living, May 2000
Heat a skillet over medium heat, and add 1/2 teaspoon oil. When oil is hot, place 1 tortilla in pan; sprinkle with 1/4 cup grated cheese, 1/4 cup filling, if using, and another 1/4 cup grated cheese. Top with second tortilla, and cook until cheese is melting and the bottom of tortilla is golden brown. Flip, and cook until golden on both sides, the cheese is melted, and the filling hot.
To serve, cut quesadillas into wedges, and serve with sour cream, salsa, and guacamole on the side, if desired. Repeat with the remaining ingredients, serving each quesadilla hot from the pan.