Start by laying a large flour tortilla flat on a clean surface. This will be your base, holding all those delightful toppings together.

On one half of the tortilla, layer a handful of mozzarella cheese, followed by fresh spinach, feta cheese, sun-dried tomatoes, kalamata olives, and finely sliced red onion.

Carefully fold the unfilled half of the tortilla over the layered ingredients to create a semicircle.

Place a skillet over medium heat and add a splash of olive oil or butter. Allow the oil to heat until it shimmers.

Carefully place the folded quesadilla in the heated skillet. Cook for about 2-3 minutes until the bottom is golden brown.

Using a spatula, gently flip the quesadilla and cook the other side for another 2-3 minutes until golden and crispy.

Once cooked, allow the quesadilla to rest for a minute and slice it into wedges for serving.