Preheat the oven to 350 degrees F. Spread 2 slices of bread with the mayonnaise. Spread the other two slices with the mustard. Place one slice of the cheese on top of the mayonnaise. Divide the turkey in half and place on top of the turkey. Lay the remaining 2 slices of cheese on top of each pile of turkey. Place the remaining slices of bread on top of the cheese. In a shallow bowl, whisk the eggs and milk together. Dip each sandwich in the egg mixture. In a skillet, melt the butter. Place the sandwiches in the pan and pan-fry until golden. Place the sandwiches on a baking sheet and place in the oven. Cook until the cheese melts. Remove from the oven. Slice in half and serve with the left-over cranberry sauce.