1 small red onion, thinly sliced (1/2 cup)
1/4 c balsamic vinegar
4 10-inch whole-wheat flour tortillas
3/4 c shredded low-fat sharp cheddar cheese
8 slices smoked deli turkey (8 oz)
1. Combine onion and vinegar in a bowl; let marinate for 15 minutes. Drain, reserving the vinegar for salad dressing.
2. Place 2 tortillas in a large nonstick skillet over mediu-high heat (they will overlap); warm for about 45 seconds, then flip. Pull the tortillas up the edges of the pan so they are no longer overlapping. Working on one half of each tortilla, sprinkle one-eighth of the cheese, cover with 2 slices of turkey, follow with one fourth of the onion and top with one-eighth of the cheese. Fold the tortillas in half, press gently with a spatula to flatten and cook until the cheese starts to melt, about 2 minutes. Flip and continue cooking until the second side is golden, 1 to 2 minutes more. Transfer to a plate and cover with foil to keep warm. Make two more quesadillas with the remaining ingredients.
3. Serve warm, accompanied by a tossed green salad, using the reserved vinegar in the dressing.