Preheat your oven to 400°F.
In a 9x9-inch baking dish, drizzle the olive oil and add the halved cherry tomatoes and chopped spinach. Toss to coat the vegetables in the oil.
Crumble the feta cheese over the vegetables evenly.
Make four small wells in the feta and vegetable mixture and crack an egg into each well.
Season the eggs with salt, pepper, oregano, and red pepper flakes if using.
Bake in the preheated oven for 20-25 minutes, or until the egg whites are set but the yolks are still slightly runny.
Remove from the oven and let cool for a minute. Garnish with fresh basil or parsley before serving.