Preheat your oven to 400°F and line a small baking sheet with parchment paper.
Dice the zucchini, red bell pepper, and red onion into small, uniform pieces.
Toss the diced vegetables with half of the olive oil, sea salt, black pepper, and garlic powder on the baking sheet.
Roast the vegetables for 15-20 minutes until they are tender and slightly caramelized at the edges.
In a medium bowl, whisk together the whole eggs and egg whites until well combined and frothy.
Heat the remaining olive oil in a non-stick skillet over medium-low heat.
Add the roasted vegetables and baby spinach to the skillet, sautéing for 1 minute until the spinach just begins to wilt.
Pour the egg mixture over the vegetables and cook slowly, gently folding with a spatula until the eggs are soft and creamy.
Remove from heat and sprinkle with crumbled feta cheese before serving warm.