Place a non-stick skillet over medium heat and cook the turkey bacon until it reaches your desired level of crispness.
Remove the bacon from the pan and set it aside on a paper towel to drain.
In the same skillet, add one teaspoon of avocado oil and sauté the fresh spinach until it is just wilted, then remove and set aside.
Wipe the skillet clean and add the remaining teaspoon of avocado oil.
Pour the egg whites into the pan and cook undisturbed until the edges begin to set and the bottom is golden.
Gently lift the edges of the omelette to let any uncooked egg whites flow underneath.
Once the top is nearly set, place the sautéed spinach and crumbled feta cheese on one half of the omelette.
Fold the omelette in half and cook for another 60 seconds until the cheese is slightly softened.
Slide the omelette onto a plate, season with black pepper, and serve immediately with the crispy turkey bacon.