I got this recipe from Taste of Home's "Quick Cooking" magazine in 2001. They are one of my son's favorite sandwiches.
1 (1 - lb) loaf French Bread (I use hoagie buns)
1/4 cup milk
1/2 tsp pepper
1/4 tsp salt
1 lb hot Italian sausage
chopped onion, optional
2 cups (8 oz) shredded Mozzarella cheese
Cut bread in half lengthwise, and carefully hollow out top and bottom of loaf, leaving a 1" shell. Cube the removed bread. In a large bowl, beat the eggs, milk, pepper and salt. Add the bread cubes and toss to coat; set aside.
In a skillet, over medium heat, cook sausage and onion until the meat is no longer pink, drain. Add the sausage to the bread mixture. Spoon filling into the bread shells, sprinkle with cheese. Wrap each in foil and bake 400 degrees for 20 - 25 minutes, or until cheese is melted and lightly browned. Cut into serving-sized slices.