2 pounds potato such as yukon gold (see cooks' notes) medium to large boiling
4 servings salt
2 tablespoons butter unsalted melted
Equipment
bowl
frying pan
sauce pan
oven
whisk
baking pan
aluminum foil
Directions
Heat oven to 375°F with rack in middle. Butter baking dish.
Peel and thinly slice potatoes into a large bowl and toss with butter.
Spread potatoes in an even layer in the baking dish.
Put flour, 1 teaspoon salt, and 1/4 teaspoon pepper in a heavy medium saucepan and slowly whisk in milk until the mixture is smooth.
Bring milk mixture just to a boil over medium heat, whisking constantly (it will thicken slightly), and pour it over the potatoes. Cover pan tightly with foil and bake in oven until potatoes are tender, 35 to 40 minutes.
Remove foil and sprinkle with cheese, if using. Reset oven to broil and broil potatoes, about 4 to 5 inches from heat, until browned and bubbling, 2 to 3 minutes.
•The term Yukon gold now loosely refers to any yellow-fleshed potato, no matter what its official name might be. Any yellow-fleshed potato will work well, as will other boiling potatoes, such as large red-skinned ones or the all-purpose type grown in Maine. Avoid baking varieties (a.k.a. russets or Idahos) for this gratin, because they become too starchy, to the point of being mushy.•If you are making the scalloped potatoes along with the meatloaf, you can bake them side by side on the same rack in the oven. If your pans won’t fit side by side, put the meatloaf in the upper third and the potatoes in the lower third. When it comes to broiling, though, broil each one separately, so that you have more control over how much each dish browns.
