01 - Set oven to 375°F (190°C) and allow to fully preheat.
02 - Drizzle 1 tablespoon olive oil into a medium oven-safe skillet or baking dish. Add chopped spinach, halved cherry tomatoes, sliced onion, and minced garlic. Season lightly with salt and black pepper, then toss well to combine.
03 - Distribute crumbled feta cheese evenly over the vegetable mixture.
04 - Drizzle remaining olive oil and sprinkle dried oregano and chili flakes evenly on top.
05 - Create four small wells within the mixture and gently crack one egg into each well.
06 - Transfer skillet to oven and bake for 15 to 20 minutes until egg whites are set and yolks are slightly runny.
07 - Remove from oven, allow to cool slightly, and serve warm.