Creating Veggie Breakfast Casserole is straightforward when you follow these steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C).
2. Grease the Baking Dish: Lightly grease a 9×13-inch baking dish with olive oil or butter.
3. Sauté Vegetables: In a skillet, heat the olive oil over medium heat. Add the diced vegetables and sauté for about 5-7 minutes until softened.
4. Mix Eggs and Milk: In a large bowl, whisk together the eggs, milk, garlic powder, onion powder, salt, and pepper.
5. Layer Ingredients: Spread the sautéed vegetables evenly in the greased baking dish. If using, add the diced potatoes on top.
6. Add Cheese: Sprinkle half of the shredded cheese over the vegetables.
7. Pour Egg Mixture: Pour the egg mixture evenly over the vegetables and cheese.
8. Top with Cheese: Sprinkle the remaining cheese on top of the egg mixture.
9. Bake: Place the baking dish in the preheated oven and bake for 35-40 minutes or until the eggs are set and the top is golden brown.
10. Cool Slightly: Remove from the oven and let cool for 5-10 minutes before slicing.

These steps will guide you in creating this incredible breakfast casserole effortlessly.