01 - Preheat oven to 375°F. Lightly grease a small 1-quart baking dish with cooking spray or 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 wilted and reduced in volume. Remove from heat and let cool slightly.
04 - In a large mixing bowl, combine crumbled feta, softened cream cheese, Greek yogurt, and half the shredded mozzarella. Mix until mostly smooth and creamy.
05 - Fold in the sautéed spinach, sliced pepperoncini, dried oregano, red pepper flakes if using, and black pepper. Mix until evenly distributed.
06 - Spoon mixture into the prepared baking dish. Top with remaining mozzarella cheese and drizzle with remaining 1 tablespoon olive oil.
07 - Bake for 20-25 minutes until the dip is bubbling around the edges and lightly golden on top.
08 - Remove from oven and let rest for 5 minutes to set. Sprinkle with fresh parsley or dill and serve with lemon wedges on the side.