In a medium mixing bowl, crack the whole eggs and add the liquid egg whites and Greek yogurt.
Whisk the egg mixture vigorously for at least 60 seconds until completely smooth and slightly aerated.
Heat a non-stick skillet over low-medium heat and add the ghee, swirling to coat the bottom of the pan.
Pour the egg mixture into the skillet and let it sit undisturbed for about 30 seconds until the edges just begin to set.
Using a silicone spatula, gently push the eggs from the outer edges toward the center, creating large, soft ribbons.
Continue to cook 'low and slow,' moving the eggs occasionally to prevent browning; the goal is a creamy, custard-like texture.
When the eggs are about 80% cooked, sprinkle in the crumbled feta cheese and chopped fresh chives.
Gently fold the cheese and herbs into the eggs for another 30 seconds, then remove the pan from the heat while the eggs still look slightly wet.
Season with sea salt and black pepper, and serve immediately alongside a fresh bed of baby spinach.