Chop the turkey bacon into small pieces.
Heat a non-stick skillet over medium heat and cook the turkey bacon until it reaches a crispy texture.
Remove the bacon from the pan and set aside on a paper towel to drain.
In a medium bowl, whisk together the whole eggs, egg whites, sea salt, and black pepper until well combined and slightly frothy.
Wipe the skillet clean and add the avocado oil, swirling to coat the surface evenly.
Pour the egg mixture into the skillet and let it set for about 1 minute without stirring.
Use a silicone spatula to gently lift the edges of the omelette, allowing the liquid egg to flow underneath.
Once the top is mostly set but still slightly moist, sprinkle the cooked turkey bacon, cheddar cheese, and baby spinach over one half of the omelette.
Carefully fold the other half over the filling and cook for another 30 to 60 seconds until the cheese is fully melted and the spinach is wilted.
Slide the omelette onto a plate and serve immediately.