Preheat barbecue grill to 350°F (medium heat) on one side only (direct heat).
For each quesadilla, lay one tortilla shell* on a cutting board or baking tray.
Layer ingredients in the order listed and top with a second tortilla shell.
Working with one quesadilla at a time, carefully place filled quesadilla on direct heat for about 90 seconds, or until the bottom is golden brown.
Using a pizza peel, or a large spatula, flip and move quesadilla to indirect heat size of the grill. Cook for 2-3 minutes or until cheese is melted.
Using a pizza peel, or a large spatula, move quesadilla to direct heat size of the grill and cook 60-90 seconds, or until the bottom is golden brown.
Cool on a rack (to keep crispy) for 1-2 minutes. Transfer to a cutting board and cut into pieces using a pizza cutter or very sharp knife.
Sprinkle with parsley and serve with salsa, sour cream, and guacamole if desired.
Notes
Each quesadilla serves 2.
*Another option is to lay out two tortilla shells, and fill half of each of the two tortilla shells with the toppings. Fold in half and grill as directed.