In a large skillet, heat a splash of olive oil over medium heat. Toss in the diced onion and sauté for about 2-3 minutes until they start to become translucent.

Add the minced garlic and sliced mushrooms, and season with a pinch of salt and pepper. Sauté until the mushrooms are tender, about 5 minutes.

Next, throw in the fresh spinach. Stir it for just a minute or two until it’s wilted down, then remove the skillet from heat. Let that delicious mixture cool for a few minutes.

Preheat your oven to 400°F (200°C). On half of each tortilla, layer a generous amount of the sautéed mixture and top with a sprinkle of shredded cheese. Fold the tortilla in half.

Arrange the quesadillas on a baking sheet lined with parchment paper. Brush the tops lightly with olive oil for a golden finish.

Bake them in your preheated oven for about 10-12 minutes, or until the tortillas are crispy and the cheese inside is melty.

Once they’re out of the oven, let them cool for a couple of minutes. Slice them into wedges and serve with your favorite salsa or a dollop of sour cream.