Preheat your oven to 375°F (190°C) and lightly grease a small oven-safe baking dish.
Heat the avocado oil in a skillet over medium heat.
Add the ground turkey sausage to the skillet, breaking it into small crumbles with a spatula until browned and cooked through.
Add the diced yellow onion and red bell pepper to the sausage, sautéing for 3-4 minutes until the vegetables are tender and fragrant.
Stir in the fresh baby spinach and cook just until wilted, then remove the skillet from the heat.
In a medium mixing bowl, whisk the eggs together with the sea salt, black pepper, and garlic powder until well combined.
Transfer the cooked sausage and vegetable mixture into the prepared baking dish, spreading it into an even layer.
Pour the whisked egg mixture over the sausage and vegetables, gently tapping the dish to ensure the eggs settle to the bottom.
Sprinkle the shredded sharp cheddar cheese evenly over the top of the egg mixture.
Bake for 20-25 minutes until the eggs are set in the center and the cheese is bubbly and golden brown.