Prepare tortilla by warming them in a dry, hot skillet or by steaming them. Keep tortillas warm. Place avocado, onion, lemon juice, salt and garlic powder in food processor. Process until smooth.
In a large bowl, mix together the avocado mixture, 1/2 cup Pepper Jack cheese, sour cream, and 1/2 cup Colby Jack cheese.
Spread avocado mixture on one side of 3 of the flour tortillas. Top with remaining tortillas and press down gently.
Preheat broiler and using a pizza cutter, cut each tortilla into 8 triangles. Place on large cookie sheet and sprinkle with remaining 1/2 cup of Colby Jack cheese. Broil about 3 minutes until cheese is just melted.
Serve with sour cream or taco sauce.
You can use any cheese you like and even substitute prepared guacamole to save you some time.
While you can certainly use corn tortillas for this appetizer, flour is softer and works better. You can make your own flour tortillas (even flavored ones!) or your favorite brand, just be sure to warm them a bit before starting.
If you happen to taste test the filling mixture before the appetizer is complete, don't be alarmed at the salty taste. The finished quesados are not too salty and come out perfect.