Preheat oven to 375. Saute ham and leek in 2 tablespoons of the butter in a large skillet until leek is tender, about 5 minutes. Spoon ham and leek over bottom of pie shell.
Beat eggs lightly in medium size bowl. Beat in milk and cream. Stir in cheese, salt, pepper and nutmeg. Pour into pie shell. Place tart on baking sheet. Bake in oven for 30 minutes or until custard is set and top is golden. Let stand 5 to 10 minutes before cutting.
Note: Turkey ham, sold in loaf form, is great for alot of things so don't let it go to waste! Its great as a substitute for ham in soups, in frittatas, or sandwiches sliced thin. My kids love to snack on it, too.