Ham and Potato Gratin

Grandpa would say these potatoes are "all rotten," but there's nothing remotely bad about this recipe. The best way to slice all the potatoes is with your new, fancy, food processor Christmas gift that does the job in less than thirty seconds - but a knife and cutting board work just fine, too : )

5 medium thick slices smoked ham (about 4 ounces)
4 tablespoons butter
2 pounds baking potatoes (4 or 5 of them), such as russets, peeled and very thinly sliced
3 cups freshly grated Gruyere cheese (we did a combination of mozzarella and cheddar instead)
1 teaspoon nutmeg, or to taste
Salt and pepper

1)Preheat the oven to 375
2) Trim all the fat from the ham. Chop into 1/2 inch to 1 inch pieces
3) Use one tablespoon of the butter to coat the inside of a baking dish about 14x9x2. Arrange half the potatoes in an even layer in the dish.
4) Arrange half the ham evenly over the potatoes. Distribute half the cheese over the ham. Season with nutmeg, salt and pepper to taste. Arrange the remaining potatoes, ham, and cheese in even layers in the dish. Sprinkle on more nutmeg, salt, and pepper. Cut the remaining butter into bits; dot the top evenly with butter.
5) Bake, uncovered, until the gratin is golden, about 50 minutes; do not overcook or the gratin will be dry and the ham rubbery. Serve immediately.