Preheat the oven to 425°F (220°C). Line two baking sheets with parchment paper or foil for easy cleanup.

Warm 2 tbsp of olive oil in a large skillet over medium heat. Add the diced onion and sauté for 3–4 minutes until soft and translucent.

Add the mushrooms and cook for 5–7 minutes until they release their moisture and start to brown. Stir in the garlic and cook another minute.

Toss in the chopped spinach, oregano, smoked paprika, salt, and pepper. Cook just until the spinach wilts, about 2 minutes. If using cream cheese, stir it in now so it melts into the mixture. Taste and adjust seasoning.

Combine the shredded cheeses in a bowl.

Lay out four tortillas on a flat surface. Spoon an even amount of the spinach-mushroom mix onto one half of each tortilla, then sprinkle generously with the cheese blend and a little cilantro if using.

Fold the tortilla over to form a half-moon. Repeat with the remaining tortillas.

Lightly brush or spray both sides of each quesadilla with olive oil. Place on the prepared baking sheets and bake for 8–10 minutes, flipping halfway through, until golden and cheese is melted.

For extra crispiness, broil for 1 minute per side at the end — watch carefully so they don't burn.

Let quesadillas rest for 2 minutes, then cut into wedges. Serve with salsa, Greek yogurt or sour cream, and a squeeze of lime.