Preheat your oven to 400°F (200°C).
In a 9-inch baking dish, drizzle the olive oil and spread the halved cherry tomatoes evenly across the bottom.
Add the fresh spinach on top of the tomatoes, distributing it evenly.
Crumble the feta cheese over the spinach and tomatoes.
Create four small wells in the feta mixture and crack an egg into each well.
Season the eggs with salt, pepper, and dried oregano.
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 garnish with fresh basil leaves if desired. Serve warm.