Prep the Ingredients. Start by preheating your oven to 375°F. Grease a 9x13-inch baking dish with cooking spray or butter to prevent sticking.
Cook the Sausage. In a skillet over medium heat, cook the breakfast sausage until browned and fully cooked. Drain excess grease and set aside.
Assemble the Casserole. Layer the hash browns evenly in the prepared baking dish. Sprinkle the cooked sausage on top, followed by the chopped veggies.
Mix the Egg Mixture. In a large bowl, whisk together the eggs, milk, salt, pepper, and paprika. Pour the mixture over the casserole ingredients, ensuring everything is evenly coated.
Add Cheese and Bake. Sprinkle shredded cheddar cheese over the top and bake for 35-40 minutes, or until the eggs are set and the top is golden brown.
Serve and Enjoy. Let the casserole cool for a few minutes before slicing. Serve with your favorite toppings like salsa, avocado, or sour cream.