Finely dice the red onion and red bell pepper into uniform pieces.
In a medium-sized bowl, whisk together the two whole eggs and the liquid egg whites until the mixture is well combined and slightly frothy.
Heat the extra virgin olive oil in a large non-stick skillet over medium heat.
Add the diced onion and bell pepper to the skillet and sauté for 4 to 5 minutes until the vegetables are softened and the onion is translucent.
Add the fresh baby spinach to the pan and toss for about 1 minute until the leaves are just wilted.
Reduce the heat to medium-low and pour the egg mixture into the skillet over the vegetables.
Let the eggs sit for 30 seconds to set slightly, then use a silicone spatula to gently push the eggs toward the center, creating soft curds.
When the eggs are about 80% cooked, sprinkle in the sea salt, black pepper, and crumbled feta cheese.
Continue to fold the eggs gently for another 30 to 60 seconds until they are fully set but still tender and the feta is warmed through.
Remove from the heat immediately and serve on a warm plate.