In a small mixing bowl, mash together avocado, olive oil, lemon juice, salt and pepper.
Lay one tortilla flat and spread mashed avocado, covering most of the open side.
Spread chopped basil, along with sliced tomatoes and crumbled feta.
Sprinkle salt and pepper to taste and cover with another tortilla.
Heat a wide open flat skillet over medium heat. Brush some cooking oil on the pan. Lay the quesadilla on the pan until golden brown, then flip and repeat. Once both sides are golden brown, remove from heat.
Slice quesadilla into pieces, like a pizza.
Serve while hot.
Notes
*Note: Use gluten-free tortillas to make this recipe gluten-free.