Heat a large skillet over medium heat and cook the ground beef until browned. Season with salt, pepper, garlic powder, and onion powder. Drain any excess fat and set aside.
In the same skillet, sauté the onions, bell peppers, and mushrooms until soft and caramelized (about 5 minutes). Set aside.
3. Assemble the Casserole:
In a large mixing bowl, whisk together the eggs and heavy cream. Add a pinch of salt and pepper.
In a greased casserole dish (9×13 inch works well), layer the cooked beef and sautéed vegetables.
Pour the egg mixture evenly over the beef and vegetables.
Top with shredded mozzarella and provolone cheese.
4. Bake the Casserole:
Bake in the preheated oven for 25-30 minutes, or until the cheese is melted and bubbly and the casserole is set in the middle.
5. Garnish and Serve:
Let the casserole cool for 5 minutes before slicing.
Garnish with fresh parsley or green onions if desired and serve hot.
