Remove and discard sausage casings.

Cook sausage in a large skillet over medium heat, breaking it apart with a spoon, until browned and no longer pink.

Drain off any excess grease.

Add sliced green onions, diced zucchini, salt, and pepper to the skillet.

Sauté for 4 minutes, or until the vegetables are tender.

Stir in the chopped roasted red peppers and remove from heat.

Let the sausage mixture cool slightly.

Grease a 13x9 inch baking dish.

Spread 4 cups of the cubed Italian bread evenly in the prepared dish.

Top with half of the sausage mixture and half of the shredded cheddar cheese.

Repeat the layers with the remaining bread, sausage mixture, and cheese.

In a separate bowl, whisk together the eggs and milk.

Pour the egg mixture evenly over the bread and sausage layers.

Cover the baking dish tightly with plastic wrap and refrigerate for at least 8 hours, or overnight.

Preheat oven to 325°F (160°C).

Remove the plastic wrap from the baking dish.

Bake, covered, at 325°F (160°C) for 1 hour.

Remove cover and bake 15 minutes more, or until bubbly and hot, and the top is golden brown.