Preheat the Oven: Preheat your oven to 350°F (177°C).

Cook the Sausage: In a large skillet over medium heat, cook the sage pork sausage until it’s browned and crumbly. Drain any excess grease and set aside.

Prepare the Vegetables: In the same skillet, add the chopped green and red bell peppers. Sauté until they are just tender, about 5 minutes.

Mix the Egg Mixture: In a large mixing bowl, whisk together the eggs, whole milk, ground black pepper, garlic powder, and salt until well combined.

Assemble the Casserole: In a 9x13 inch baking dish, evenly spread the frozen hash browns. Sprinkle the cooked sausage over the hash browns, followed by the sautéed bell peppers. Pour the egg mixture over the sausage and vegetables, making sure it’s evenly distributed. Evenly sprinkle the shredded cheddar cheese on top.

Bake the Casserole: Place the dish in the preheated oven and bake uncovered for 40 minutes. After 40 minutes, sprinkle the crispy fried onions over the top of the casserole. Cover the dish with aluminum foil and return it to the oven. Bake for an additional 10 minutes, or until the eggs are set and the cheese is bubbly.

Serving: Let the casserole stand for a few minutes after removing it from the oven. Serve hot, with hot sauce on the side if desired.