In a large mixing bowl, whisk together eggs, milk, heavy cream, salt, pepper, garlic powder, and onion powder until smooth and well combined.
Grease a 9x13-inch baking dish. Layer the cubed bread evenly at the bottom. Sprinkle the cooked sausage and bacon over the bread, followed by the shredded cheddar and mozzarella cheese.
Pour the egg mixture evenly over the layers in the baking dish. Cover with foil and refrigerate overnight to allow the flavors to blend beautifully.
Preheat your oven to 350°F (175°C). Remove the casserole from the fridge and let it sit for 15 minutes at room temperature. Bake uncovered for 40-45 minutes or until the top is golden brown and the center is set. Garnish with parsley and serve hot!