Preheat your oven to 350°F. While the oven heats, lightly spray a 9x13 inch baking dish (or similar size) with cooking spray or oil to prevent sticking. This gives you time to prep ingredients while the oven reaches temperature.

Heat the olive oil in a large skillet over medium-high heat. Once shimmering, add the minced garlic and cook for about 30 seconds until fragrant, then immediately add the diced onion, broccoli florets, and red bell pepper. Sauté for 8 minutes, stirring occasionally, until the vegetables are tender but still have some color. I like to cook the garlic quickly before adding the other vegetables so it doesn't burn and become bitter.

In a large mixing bowl, crack the 4 large eggs and add the 4 egg whites. Whisk together until well combined and slightly frothy. Pour in the milk and whisk again until the mixture is smooth and homogeneous. This creates the custard base that will set during baking.

To the egg and milk mixture from Step 3, add the salt, black pepper, dried oregano, and dried basil. Stir well to combine. Then fold in the shredded mozzarella and crumbled feta cheese until evenly distributed. The cheese will add richness and flavor throughout the quiche.

Spread the cooked vegetables from Step 2 evenly in the prepared baking dish. Pour the cheese and egg mixture from Step 4 over the vegetables, making sure they're evenly distributed. Place the dish in the preheated 350°F oven and bake for 40 minutes, until the center is just set but still slightly jiggly in the very middle—it will continue to cook slightly as it cools.

Remove the quiche from the oven and let it rest at room temperature for 10 minutes. This resting period allows the eggs to finish setting and makes the quiche easier to slice cleanly. I find that skipping this step results in a quiche that's too soft and falls apart when you serve it.