Heat The Oven To 400 Degrees F. Remove The Bread From The Bag. Place The Frozen Bread Halves, Cut-Side Up, On An Ungreased Baking Sheet. (If The Bread Halves Are Frozen Together, Carefully Insert A Fork Between Halves To Separate.) Place Baking Sheet On The Middle Oven Rack. Bake For 10 Minutes Or Until It'S Hot. Heat The Sauce And Meatballs In A 2-Quart Saucepan Over Low Heat. Cook And Stir For 20 Minutes Or Until The Meatballs Are Heated Through. Place The Meatballs Onto The Bottom Bread Half. Top With The Remaining Bread Half. Cut Into Quarters.