Finely dice the red onion, red bell pepper, and chicken sausage into uniform bite-sized pieces.
In a small mixing bowl, whisk together the whole eggs and liquid egg whites until well combined and slightly frothy.
Heat the extra virgin olive oil in a non-stick skillet over medium heat.
Add the diced chicken sausage, onion, and bell pepper to the skillet, sautéing for 4-5 minutes until the vegetables are tender and the sausage is lightly browned.
Lower the heat to medium-low and pour the egg mixture into the skillet.
Add the baby spinach to the pan and gently stir with a silicone spatula, folding the eggs over the vegetables and sausage.
Continue to cook, stirring occasionally, until the eggs are just set and the spinach has wilted.
Remove from heat and season with sea salt and black pepper.
Transfer the scramble to a plate and top with fresh slices of avocado before serving.