Slice the smoked turkey sausage into 1/4-inch rounds and finely dice the red onion and red bell pepper.
In a medium bowl, whisk together the large eggs, egg whites, sea salt, and black pepper until the mixture is uniform and slightly frothy.
Heat the avocado oil in a large non-stick skillet over medium-high heat until shimmering.
Add the turkey sausage rounds to the skillet and cook for 3-4 minutes, turning once, until they are browned and slightly crispy.
Add the diced onion and bell pepper to the pan and sauté for 3 minutes until the vegetables are tender and fragrant.
Toss in the baby spinach and stir for 1 minute until the leaves just begin to wilt.
Reduce the heat to medium-low and pour the egg mixture into the skillet over the sausage and vegetables.
Gently fold the eggs with a silicone spatula, moving from the edges toward the center, until they are set but still soft.
Sprinkle the nutritional yeast over the scramble and fold once more to incorporate the savory flavor.
Remove from heat immediately and serve while the eggs are fluffy and warm.