Preheat your oven to 375°F (190°C) and lightly grease a small oven-safe baking dish.
Heat the extra virgin olive oil in a skillet over medium heat.
Add the diced yellow onion and red bell pepper, sautéing for 3-4 minutes until the onion is translucent.
Add the ground turkey sausage to the skillet, breaking it up with a spatula, and cook until browned and fully cooked through.
Stir in the fresh baby spinach and cook for 1 minute until just wilted, then remove the skillet from heat.
In a medium bowl, whisk together the eggs, liquid egg whites, sea salt, black pepper, and dried oregano until well combined.
Spread the sausage and vegetable mixture evenly into the prepared baking dish.
Pour the egg mixture over the sausage and vegetables, ensuring everything is evenly covered.
Sprinkle the crumbled feta cheese over the top.
Bake for 20-25 minutes, or until the eggs are set in the center and the edges are slightly golden.
Let the bake rest for 5 minutes before slicing and serving.