Sausage, Cheese, And Egg Casserole

• 12 herb seasoned croutons
• 4 ggs
• 700 ml milk
• 400 gr mild bulk sausage
• 230 gr sharp cheddar cheese (grated)
• 4 ml dry mustard
• 1 gr salt
• 1 gr pepper
• 1 package cream of mushroom soup