Preheat your oven to 375°F (190°C) and lightly grease a small oven-safe baking dish with the olive oil.
Place a skillet over medium heat and sauté the diced onion and red bell pepper until they begin to soften, about 3-4 minutes.
Add the ground turkey sausage to the skillet, breaking it into small crumbles with a wooden spoon, and cook until it is completely browned.
Add the fresh spinach to the skillet and stir for 1 minute until the leaves are just wilted, then remove the pan from the heat.
In a medium mixing bowl, whisk together the large eggs, egg whites, sea salt, black pepper, garlic powder, and dried oregano until well combined.
Spread the cooked sausage and vegetable mixture evenly across the bottom of the prepared baking dish.
Pour the egg mixture over the sausage and vegetables, ensuring the liquid is distributed evenly.
Bake for 20-25 minutes, or until the eggs are fully set in the center and the top is a beautiful golden-brown.