Preheat your oven to 400°F (200°C) and line a small baking sheet with parchment paper.
Toss the diced red bell pepper and red onion with olive oil, sea salt, and black pepper directly on the baking sheet.
Roast the vegetables for 15-20 minutes until they are tender and show slight caramelized edges.
While the vegetables roast, whisk together the whole eggs, liquid egg whites, and garlic powder in a medium bowl until well combined.
Heat a non-stick skillet over medium-low heat. Pour in the egg mixture and let it sit for 30 seconds.
Using a silicone spatula, gently push the eggs from the edges toward the center to create soft curds.
When the eggs are nearly set but still slightly moist, fold in the roasted vegetables and the fresh baby spinach.
Continue to cook for 1 minute until the spinach is just wilted and the eggs are fully cooked through.
Remove from heat, transfer to a plate, and sprinkle with the crumbled feta cheese before serving.