Preheat oven to 350 degrees.
Spray in a 9 x 13 baking dish and set aside.
In a medium sauté pan heat 1 tablespoon of olive oil over medium heat. Add the sliced mushrooms and cook until tender, about 5 minutes. Place the cooked mushrooms into the baking dish.
Using the same pan, heat the last tablespoon of olive oil over medium heat. Add the onion and bell pepper and cook until onion is translucent and both vegetables are tender.
While the onions and peppers are cooking heat the broccoli in the microwave until it's heated through. Then add the broccoli to the pan with the onions and peppers. Break up the broccoli into small pieces as it cooks completely.
Place the rest of the vegetables into the baking dish.
In a large mixing bowl (you can do this step while the vegetables are cooking) whisk the eggs, milk, garlic powder, onion powder, salt, and pepper.
Pour the egg mixture over the vegetables and then give it a couple slow stirs.
Place the dish into the oven and bake for 40 - 45 minutes or until the center is set.