In a medium skillet, heat 1 tablespoon of olive oil over medium heat. Once shimmering, add 2 minced garlic cloves and sauté for about 30 seconds until fragrant.

Add 2 cups of chopped fresh spinach to the skillet. Cook for about 2-3 minutes, stirring, until the spinach wilts down. Season with salt, pepper, and 1 teaspoon of dried oregano.

Lay out your whole wheat tortillas. Evenly distribute the sautéed spinach mixture over half of each tortilla, leaving edges clear.

Sprinkle crumbled feta cheese and shredded mozzarella over the spinach, followed by thinly sliced red onions.

Fold each tortilla in half to create a half-moon shape, pressing down gently.

Heat a non-stick skillet over medium-high heat. Lightly coat with cooking spray or olive oil. Cook folded quesadillas for about 2-3 minutes per side until golden and crispy.

Transfer cooked quesadillas to a cutting board, allow to cool for 1 minute, then slice into wedges.

Serve warm with tzatziki sauce for dipping or alongside a salad.