Place zucchini, peppers and onion on a baking sheet. Drizzle with oil, sprinkle with salt and pepper and roast for 15 minutes.
Remove from the oven, add the garlic, toss again and roast for 15 more minutes.
While the vegetables are roasting, whisk together the eggs, half and half and a sprinkle of salt and pepper.
Heat the butter in an oven proof skillet over medium low heat. Add the green onions and sauté for a minute or so.
Add the roasted vegetables to the skillet. Sprinkle with Parmesan cheese and pour the egg mixture even over the vegetables.
Cook for about 2 minutes and then put the skillet in the oven. Bake for 20-30 minutes.
Remove from the oven, top with the Gruyere cheese and bake for about 3 more minutes.
Video
Notes
Vegetable variations - it is so easy to make this seasonal.Use summer squash, tomatoes, and green beans in the summer.In the fall and winter use sweet potatoes, winter squashes, fennel, cauliflower. Cheese variations:fontina, mozzarella, feta.... any cheese you'd like!