Follow these steps to create your perfect Hopple Popple Breakfast Casserole:

1. Cook the Hash Browns and Onion
   In a large skillet over medium-high heat, melt the butter. Add the hash browns and onion, cooking until they are golden brown. Spread the mixture evenly in the pan to form a base layer for your casserole.
2. Prepare the Egg Mixture
   In a separate bowl, whisk together the eggs, milk, salt, pepper, and Italian herbs. This mixture will hold the casserole together, infusing it with flavor.
3. Combine and Cook
   Pour the egg mixture over the potato layer in the skillet, ensuring it’s evenly distributed. Place the turkey pepperoni slices on top. Cover the skillet and cook on low for 10-15 minutes, or until the eggs are set.
4. Add the Cheese
   Remove the lid and sprinkle the shredded sharp cheddar and mozzarella cheeses over the top. Cover the skillet again and let it sit for 2-3 minutes with the heat turned off, allowing the cheese to melt beautifully.
5. Serve
   Once the cheese has melted, cut the casserole into wedges and serve it warm. Enjoy the melty cheese, savory pepperoni, and crispy hash browns in every bite.