Preheat your oven to 350°F and grease a 9x13 inch baking dish with butter or cooking spray. While the oven heats, brown the pork sausage in a large skillet over medium-high heat, breaking it into small crumbles as it cooks, about 5-7 minutes. Once the sausage is fully cooked and no longer pink, carefully drain off the excess fat by tilting the skillet and using a spoon to push the sausage to the side. Set the cooked sausage aside on a paper towel-lined plate.

While the sausage cooks, dice the onion into small pieces and dice both the red and green bell peppers into 1/4-inch pieces—uniform sizing helps them cook evenly. In the prepared baking dish, combine the hash browns (straight from the freezer—no need to thaw), the browned sausage from Step 1, the diced onion, both diced peppers, and 1.5 cups of the freshly shredded cheddar cheese. Mix everything together gently with a fork or your hands until well distributed. I like to use freshly shredded cheese rather than pre-shredded because it melts much more smoothly and creates a better texture throughout the casserole.

In a large bowl, crack all 8 eggs and whisk them together until the whites and yolks are fully combined. Add the evaporated milk, Italian seasoning, salt, black pepper, and garlic powder. Whisk everything together until smooth and well blended—make sure there are no streaks of egg white remaining. The evaporated milk creates a richer, more custardy texture than regular milk, which gives the casserole better structure and flavor.

Pour the egg custard mixture from Step 3 evenly over the hash brown and sausage base in the baking dish, making sure it flows around all the ingredients. Sprinkle the remaining 1 cup of shredded cheddar cheese over the top, creating an even layer. Place the casserole in the preheated 350°F oven and bake for 55-65 minutes, until the eggs are set but still slightly jiggly in the very center when you gently shake the pan—this means it will be creamy rather than rubbery when served. The top should be golden brown and the edges should pull slightly away from the sides of the dish.