In a large saucepan, cook ground beef and onion over medium heat until meat is browned, about 8 minutes. Drain grease.
Add Dei Fratelli Tomato Sauce and season with salt and pepper. Mix well and heat through, about 2 minutes. Place mixture in a large baking dish. Evenly cover with mozzarella, then top with croutons.
In a small bowl, whisk together eggs, milk, and Italian seasoning. Pour over entire dish. Cover with foil and bake for 1 hour.
Serve with your choice of dinner rolls and toppings to make mini sandwiches, or use as a filling in warm tortillas and top with lettuce and tomatoes. This is a great option for a hassle-free dinner with leftovers!