Given the task definition and input, reply with output. In this task, you will be presented with the directions of a recipe separated by "," and have to fill in the "___" which is a step that is missing from the recipe.

Butter 9 x 13-inch baking pan.,Lay 8 slices of bread on bottom of pan.,Sprinkle cheese, ham and vegetables, if desired, over bread.,Put 8 more slices on top.,Beat together eggs, milk, salt and dry mustard.,Pour over bread slices in pan.,______
Cover with foil and refrigerate overnight.