In a medium bowl, whisk together the eggs, liquid egg whites, Greek yogurt, sea salt, black pepper, and garlic powder until the mixture is completely smooth and slightly frothy.
Place a large non-stick skillet over medium heat and add the ghee, swirling to coat the bottom of the pan.
Add the cherry tomatoes to the skillet and sauté for 2 to 3 minutes until the skins begin to blister and soften.
Add the baby spinach to the pan and cook for about 1 minute, tossing frequently until the leaves are just wilted.
Reduce the heat to medium-low and pour the egg mixture into the skillet over the vegetables.
Using a silicone spatula, gently push the eggs from the edges toward the center, creating large, soft curds while keeping the texture moist.
When the eggs are almost set but still look slightly wet, sprinkle the crumbled feta cheese evenly over the top.
Remove the skillet from the heat immediately and let the residual heat finish cooking the eggs for 30 seconds before serving.