I got this recipe from Betty. It's been our breakfast on Christmas morning for several years running, and I see no reason to mess with a tradition that's working for us. You make this the night before and pop it in the oven while everyone's opening presents. It's delicious and has a nice protein punch to counteract all of the cookies and candy canes you'll be consuming in lieu of an actual lunch.
1 loaf potato bread
2 T Dijon mustard
8 oz thinly sliced cooked ham
8 oz thinly sliced cheese
4 eggs
2 C milk
1/4 C grated Parmesan cheese
1/4 C plain bread crumbs
3 T butter or margarine, melted
In ungreased 13" x 9" (3 qt) glass baking dish, arrange half of the bread slices, overlapping as needed. Brush bread in dish with mustard. Top evenly with ham and cheese, overlapping as needed. Top with remaining bread slices, arranging them over first layer of bread slices to make sandwiches.
In medium bowl, beat eggs and milk with wire whisk until well blended. Carefully pour over sandwiches. Cover; refrigerate at least 1 hour but no longer than 12 hours.
Meanwhile, in small bowl, mix Parmesan cheese, bread crumbs, and butter. Set aside.
Heat oven to 375°F. Sprinkle crumb topping over casserole. Bake uncovered 30 to 35 minutes or until sandwiches are puffed and golden brown.