Preheat your oven to 375°F (190°C).
Heat the avocado oil in a small 8-inch oven-safe cast iron skillet over medium heat.
Dice the chicken apple sausage, red bell pepper, and yellow onion into small, uniform pieces.
Add the sausage, peppers, and onions to the skillet and sauté for 5-6 minutes until the vegetables are soft and the sausage is lightly browned.
Add the baby spinach to the skillet and stir for 1 minute until just wilted, then remove the skillet from the heat.
In a medium mixing bowl, whisk together the large eggs, egg whites, sea salt, black pepper, and smoked paprika until well combined and frothy.
Pour the egg mixture over the sautéed ingredients in the skillet, ensuring the vegetables are evenly distributed.
Sprinkle the shredded sharp cheddar cheese evenly across the top of the eggs.
Transfer the skillet to the preheated oven and bake for 12-15 minutes, or until the eggs are set in the center and the cheese is melted and golden.
Remove from the oven and let rest for 2 minutes before slicing and serving directly from the skillet.