01 - Preheat oven to 375°F. Lightly grease a small 1-quart baking dish with olive oil or cooking spray.
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 of 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 throughout the cheese mixture.
06 - Spoon the mixture into the prepared baking dish, spreading evenly. Top with 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 lightly golden brown on top. The cheese should be fully melted and slightly browned.
08 - Remove from oven and let sit for 5 minutes to set. Garnish with freshly chopped parsley or dill and serve with lemon wedges on the side.