1. Generously butter or spray a 9×13-inch baking dish. If bread is fresh, cut into 1-inch cubes and let dry overnight, or toast at 300°F for 10 minutes.

2. In a large skillet over medium heat, cook breakfast sausage for 8-10 minutes, breaking into small crumbles until fully browned with no pink remaining. Drain excess fat leaving 1 tablespoon, then let cool 5 minutes.

3. Spread half of the bread cubes evenly in the prepared baking dish.

4. Sprinkle cooked sausage over the bread layer, followed by 2 cups of the mixed shredded cheddar and Monterey Jack cheese.

5. Top with remaining bread cubes, creating even layers throughout the dish.

6. In a large mixing bowl, whisk together eggs, milk, heavy cream, Dijon mustard, salt, pepper, garlic powder, onion powder, and paprika until completely smooth with no egg white streaks.

7. Pour custard mixture evenly over the layered bread and sausage. Use a spatula to gently press bread cubes down, ensuring all pieces are soaked in the egg mixture.

8. Cover tightly with plastic wrap or aluminum foil and refrigerate for at least 4 hours or overnight (up to 24 hours).

9. Remove from refrigerator 30 minutes before baking. Preheat oven to 350°F.

10. Bake covered with foil for 45 minutes.

11. Remove foil, sprinkle remaining ½ cup cheddar cheese on top, and bake uncovered for 15-20 minutes until center is set (no jiggling), top is golden brown, and internal temperature reaches 160°F.

12. Let rest for 10 minutes before serving. Garnish with fresh chives or parsley. Cut into squares and serve warm.