Begin by preparing your ingredients. Wash and roughly chop about two cups of fresh spinach. Crumble half a cup of feta cheese and shred one cup of mozzarella cheese.

Place a large skillet on medium heat and lightly grease it with a tablespoon of olive oil or butter. Allow the skillet to warm for about 2 minutes.

Once heated, lay a tortilla flat in the skillet. Layer a generous handful of the prepared spinach, sprinkle the crumbled feta, and add the shredded mozzarella on one half.

Fold the tortilla over the filling, forming a half-moon shape. Cook for 2-3 minutes until edges start to turn golden brown.

Carefully flip the quesadilla over using a spatula and cook another 2-3 minutes until crispy.

Monitor the cooking heat to ensure the cheese melts thoroughly without burning. Adjust heat as needed.

Remove the quesadilla from the skillet, let cool slightly, cut into wedges, and serve warm.