Preheat the oven to 350°F. Grease a 9x13-inch baking dish.
In a large skillet over medium heat, cook the sausage until browned and crumbled, about 5-7 minutes. Drain excess fat.
In a large bowl, whisk together the eggs, milk, garlic powder, salt, black pepper, and paprika until well combined.
Add the cooked sausage, bell peppers, onion, and half of the cheddar cheese to the egg mixture. Stir to combine.
Fold in the cubed bread until evenly coated with the egg mixture.
Pour the mixture into the prepared baking dish and spread it out evenly. Top with the remaining cheddar cheese.
Bake for 30-35 minutes, or until the casserole is set in the center and the top is golden brown.
Let it cool for 5-10 minutes before slicing and serving.