01 -
Preheat oven to 325°F. Spray a 9×9-inch casserole dish with cooking spray, and set aside.
02 -
In a medium skillet, heat the olive oil over medium heat. Add the onions and cook until they are soft.
03 -
Add broccoli, mushrooms, cherry tomatoes, and spinach to the skillet. Sauté until tender, then transfer the mixture to the baking dish and set aside.
04 -
Whisk together the eggs, almond milk, garlic powder, mustard powder, salt, and pepper in a bowl.
05 -
Pour the egg mixture evenly over the vegetables in the baking dish. Sprinkle the cheese on top.
06 -
Cover the dish with foil and bake for 40 minutes. Remove the foil and bake for an additional 10 minutes, or until the egg mixture is set.
07 -
Let the casserole cool for 5 minutes before serving.