Preheat your oven to 350°F (175°C). While the oven is heating, lightly grease a 9x13-inch casserole dish to prevent sticking. I like to use a bit of olive oil or nonstick spray for this step for easy cleanup later.

In a large skillet over medium-high heat, crumble and brown the sausage until it is fully cooked through and nicely browned. If you are using turkey sausage, you may need to add a little oil to prevent sticking. Once cooked, transfer the sausage to a large bowl and set aside.

Using the same skillet, add the diced red bell pepper, diced green bell pepper, and finely chopped onion. Sauté over medium heat, stirring occasionally, until the vegetables are softened and fragrant. If needed, add a touch of oil to keep things from sticking.

Add the frozen hash brown potatoes to the prepared casserole dish. Top with the cooked sausage from Step 2 and sautéed vegetables from Step 3. Add 2 cups of the grated cheese and mix everything well to distribute evenly throughout the dish.

In a separate bowl, whisk together the eggs, milk (or evaporated milk/cream), salt, dried parsley flakes, and ground black pepper until well combined. I like to whisk the eggs until just frothy—it makes the casserole a bit fluffier.

Pour the egg mixture from Step 5 evenly over the mixture in the casserole dish. Sprinkle the remaining 1 cup of grated cheese on top. Cover the dish with foil and bake in the preheated oven for 40–50 minutes, or until the eggs are set in the center. If you like a browned top, uncover and broil for a few minutes at the end.

Remove the casserole from the oven and let it cool slightly before slicing and serving. For an extra pop of flavor, I sometimes sprinkle a little extra parsley on top before serving. Enjoy!