Preheat your oven to 400°F (200°C) and line a small rimmed sheet pan with parchment paper.
Place the diced bell peppers, red onion, and ground turkey on the sheet pan, drizzling with olive oil and seasoning with half of the salt, pepper, and garlic powder.
Roast the vegetables and turkey for 10 minutes until the vegetables are tender and the turkey is mostly cooked through.
In a medium bowl, whisk together the large eggs, liquid egg whites, and the remaining seasonings until well combined and slightly frothy.
Remove the pan from the oven, stir in the chopped baby spinach, and spread the mixture evenly across the surface.
Carefully pour the egg mixture over the roasted ingredients, ensuring it reaches all corners of the pan.
Return the pan to the oven and bake for 12-15 minutes, or until the eggs are completely set and the edges are golden brown.
Slice into squares and serve immediately.