01 - Preheat your oven to 375°F. Lightly grease a 9-inch pie dish with cooking spray or olive oil.
02 - Evenly spread the spinach, cherry tomatoes, bell pepper, and red onion in the bottom of the prepared pie dish.
03 - In a medium bowl, whisk together the eggs, milk, salt, pepper, dried thyme, and garlic powder until well combined.
04 - Pour the egg mixture evenly over the vegetables.
05 - Sprinkle the cheddar and feta cheese over the top.
06 - Bake for 35-40 minutes, or until the quiche is set in the center and lightly golden on top.
07 - Remove from oven and let cool for 5 minutes before slicing. Serve warm or at room temperature.