Heat the skillet by drizzling olive oil into a non-stick skillet, heating it over medium heat for 1-2 minutes until it shimmers.

Add 2 cups of fresh spinach to the skillet, cooking for 2-3 minutes until wilted.

In a mixing bowl, combine the sautéed spinach with crumbled feta, shredded mozzarella, chopped sun-dried tomatoes, and sliced olives.

Return skillet to medium heat, place a tortilla in the center, spoon half of the filling onto one half, fold and press down.

Cook folded quesadilla for 3-4 minutes until golden brown, flip and cook the other side for an additional 3-4 minutes.

Remove the quesadilla from the skillet, let cool for a minute, slice into wedges, and serve warm.