01 - Preheat oven to 375°F. Lightly grease a 1-quart baking dish with cooking spray or a small amount of olive oil.
02 - Heat 1 tablespoon olive oil in a skillet over medium heat. Add minced garlic and sauté for 30 seconds until fragrant, being careful not to burn.
03 - Add chopped spinach to the skillet. Sauté for 2-3 minutes until completely wilted. Remove from heat and set aside to cool slightly.
04 - In a large bowl, combine crumbled feta, softened cream cheese, Greek yogurt, and half the mozzarella. Mix with a spoon or spatula until mostly smooth and well incorporated.
05 - Add the wilted spinach, sliced pepperoncini, oregano, red pepper flakes if using, and black pepper. Fold gently until evenly distributed throughout the cheese mixture.
06 - Transfer the mixture to the prepared baking dish, spreading it evenly. Top with the remaining mozzarella cheese and drizzle with the remaining 1 tablespoon olive oil.
07 - Bake for 20-25 minutes until the dip is bubbling around the edges and the top is lightly golden. The cheese should be fully melted.
08 - Remove from oven and let sit for 5 minutes to firm up slightly. Garnish with chopped fresh parsley or dill. Serve warm with lemon wedges on the side if desired.