Baking potatoes, boiling potatoes, new potatoes, and fingerling potatoes—there are many kinds of each to choose from, some yellow, some blue or red. The red-skinned potatoes oft en called boiling potatoes have dense, white, waxy flesh that holds its shape when boiled. They won’t do very well for baking and make terrible mashed potatoes, turning gluey when mashed. Baking potatoes usually have light brown skins with white flesh that is dry and fluff y when cooked. These are best for baking and for French fries. Kennebecs and russets are common varieties. The tastiest, most versatile potatoes are the yellow-fleshed varieties such as Yellow Finn, German Butterball, and Yukon Gold. The flesh of these potatoes has a texture between that of a baker and a boiler. They have enough waxy starch to hold together when boiled, but not so much that they can’t be mashed—and best of all they are full of flavor, much more so than any white-fleshed variety. New potatoes are those that are dug while the plants are still green in the fields and have thin shaggy skins. They are a real treat. Fingerlings are smaller potatoes shaped, as you might guess, like long thin fingers. Some delicious varieties to try are Russian Banana, German, and Ruby Crescent. Select potatoes that are firm and free of discolored spots. Don’t buy potatoes that have green on the skin. This is caused by exposure to light and may indicate the presence of solanine, which is toxic. The green may be peeled away, but it is better to avoid having to do so. Store potatoes in a bag or cupboard away from any light. New potatoes and fingerlings never need to be peeled; just wash them well before cooking. Other potatoes should be peeled, depending on the recipe and your wishes. Once peeled, potatoes should be kept submerged in water to keep them from turning brown. I like this best when the potatoes are sliced quite thin (a mandoline makes this easy): that way the potato slices are less likely to curl up and burn on the edges. Yukon Gold and other waxy, yellow-fleshed potatoes keep their texture in a gratin; floury potatoes like russets fall apart.
Recipe information
Yield
4 servings
Ingredients
Preparation
Step 1
Rub a 9- by 12-inch gratin dish with: Butter.
Step 2
Peel and slice about 1/16 inch thick: 4 large yellow potatoes (about 1 1/2 pounds).
Step 3
Make a layer of potato slices in the gratin dish, overlapping them slightly, like shingles. Sprinkle with: Salt and fresh-ground black pepper.
Step 4
Continue to layer the potato slices, seasoning each layer, until the potatoes are used up. You should have two or, at the most, three layers. Carefully pour over the potatoes: 1 cup milk.
Step 5
The liquid should come up to the bottom of the top layer of potatoes. Add more if necessary. Generously dot the top of the potatoes with: 3 tablespoons butter, cut into pieces.
Step 6
Bake in a 350°F oven until browned and bubbling, about 1 hour. Halfway through the baking, take the gratin dish out of the oven and press the potatoes flat with a metal spatula to keep the top moist. Return to the oven and keep checking. The gratin is done when the potatoes are soft and the top is golden brown.
Variations
Step 7
Peel and smash a garlic clove and rub it all over the inside of the gratin dish before buttering it.
Step 8
Use duck fat instead of butter.
Step 9
Use heavy cream or a mixture of half-and-half and cream. Omit the butter.
Step 10
Substitute celery root, parsnip, or turnip slices for up to half the potatoes.
Step 11
Add chopped herbs such as thyme, parsley, chives, or chervil between the layers.
Step 12
Sauté mushrooms, sorrel, spinach, or leeks, and layer them between the potato slices.
Step 13
Sprinkle grated Gruyère or Parmesan cheese on each layer and sprinkle more on top for the last 15 minutes of baking.
