In a 9-inch skillet, melt butter over medium heat and cook onion and pepperoni together until onion starts to become translucent, about 3 minutes. Add new potatoes, tomatoes and oregano, and ½ teaspoon salt. Stir and cook for another 5 minutes.
Add spinach and with a spoon create 4 nests in potatoes for eggs to cook in, add eggs and then cover and cook for 2-4 minutes depending on your egg preference. Garnish with basil leaves and dollops of ricotta cheese. Season with salt if needed and serve.