Potato Gratin

photo: Eric Diesel

In the previous column, I wrote about Steak Diane and its hallowed place as a dish you prepare for a special occasion. In our urban home, getting through the week qualifies for that distinction, and so we labeled our Steak Diane Weeknight Dinner. This surprised some readers. A steak dinner always carries with it the message of a special evening, and that often means a trip to the steakhouse. I never say no to an evening out, I also believe that evenings at home can, and should, be special too.

I've written before of my veneration for Julia Child. Among the other things we have to thank her for, Julia is one of the lifestyle idols we have to thank for bringing steak out of the restaurant and into the home kitchen. In Mastering the Art of French Cooking and The French Chef, Child taught us that there could be more to steak than stoking the grill (though there's certainly nothing wrong with that). Because she came from the tradition of French cooking, Child taught us that cuisine's methods for attentively preparing and cooking the steak. But she taught us that within the broader context of an aesthetic of living, in which one is prepared to do one's very best with whatever one has, and in which one prepares a steak dinner not despite the fact that it's dinner at home but precisely because it is dinner at home.

Potatoes are the standard accompaniment for steak. Steak Frites aux Poivres is the classic combination, with authentic frites cut matchstick thin and fried just until crispy, jamais burnt or mealy. Steak Diane is traditionally served over a piping of whipped potatoes. But how about serving your steak alongside a wedge of creamy Gratin Dauphinoise, fragrant with garlic and herbs and nestled under a blanket of smoky gruyère?

If you grew up in the American suburbs, you call dauphinoise "au gratin" and there's a good chance you think it comes out of a box. A gratin is a form of cooking en casserole, this one consisting of meat, vegetables (or both) baked in the oven under a golden canopy of toasted breadcrumbs or melty cheese (or both). If your gratin is made with potatoes it's dauphinoise. Here is a recipe for Gratin Dauphinoise, which is simple to cook and delicious to eat. Serve with your steak dinner or, as would not be uncommon at a table française, with hamburgers. And as you eat, remember to thank French cooking and great French cooks -- for in preparing and eating your gratin dauphinois, you are truly thinking, and cooking, outside of the box.

POTATO GRATIN

The best potatoes for gratin dauphinoise are regular baking potatoes. Do not skip the soaking and marinating steps; they only take a few extra moments of planning and effort and the result will be potatoes that hold their shape in the heavy sauce while cooking to tenderness. The best gruyère will be available at a cheese shop, but you can probably get a good one in the import cheese case at the grocery store. This recipe serves four to six.

2 pounds baking potatoes
3 medium cloves garlic
4 sprigs fresh thyme
2 cups whole milk, plus more if needed
1 6-8 ounce wedge aged gruyère
1 teaspoon salt (Greek sea salt works well)
Freshly ground black pepper
Unsalted butter

12 hours before

1. Fill a large bowl halfway with cold water and place it near your work surface.

2. Working one at a time, peel each potato until the flesh is clean. Use the peeler or the tip of a paring knife to remove and discard any holes, eyes or brown spots. As you peel each potato, place it in the bath of cold water.

3. Once all of the potatoes are peeled, measure the milk into a large bowl. Tie the thyme sprigs with a length of kitchen twine and place into the milk.

4. Peel each garlic clove and remove the root ends. Half each clove; remove and discard any sprouting from the center. Use a garlic press to press each half-clove into the milk. Stir the milk until the garlic and thyme start to give off their fragrance.

5. Working one potato at a time, remove a soaked potato from the water bath (the water should be cloudy from the starch that has leached into it) and lay it on a clean cutting board dedicating to preparing vegetables. Use a strong sharp knife to cut the potato into coins 1/8 inch thick. Inspect the coins to make sure that none have insect holes; if any do, discard them.

6. Scrape the sliced potatoes into the bowl containing the seasoned milk. Make sure all of the potatoes are submerged; add more milk if needed. Cover the bowl with plastic wrap and refrigerate overnight or a minimum of 12 hours.

1-1/2 to 2 hours before

1. Postion the cooking rack in the center of the oven and heat the oven to 450 degrees F.

2. Liberally smear the inside of a clean 10-inch ceramic or metal baking dish with unsalted butter.

3. Remove the bowl containing the marinating potatoes from the refrigerator. Remove the plastic wrap; the mixture should be very fragrant and should have thickened somewhat.

4. Use a slotted spoon to transfer the potatoes to the baking dish. Use the spoon or your hands to spread the potatoes evenly across the dish.

5. Remove the thyme sprigs from the milk remaining in the dish, shaking the herbs to return excess liquid if any to the bowl. Add the salt and several grindings of fresh black pepper to the milk remaining in the bowl. Stir the mixture to incorporate all of the ingredients.

6. Carefully pour the milk into the dish containing the potatoes. Use a rubber spatula to get all of the liquid out of the bowl and into the baking dish. Use the spatula to gently separate the potato layers to ensure that the milk and its ingredients are well distributed throughout the dish.

7. Remove the wrapper and rind if any from the gruyère. Use a handheld grater to grate the cheese directly across the top of the gratin, making sure to cover the entire top surface of the gratin with the cheese.

8. Use the tip of a knife to take a dot of butter and to place the butter on the top of the grated gruyère. Repeat until entire gratin is dotted with butter.

9. Spray the shiny side of a piece of aluminum foil large enough to cover the baking dish with a thin layer of non-stick cooking spray. Lay the foil sprayed-side down across the top of the baking dish and crimp the foil on the sides, so that it clings to the baking dish but has minimal contact with the top of the gratin.

10. Carefully transfer the baking dish to the center rack of the oven. Bake undisturbed for 30 minutes.

11. After 30 minutes, carefully peel back the foil, standing clear to avoid escaping steam, and test the gratin with the tip of the knife. The potatoes should be tender and the cream sauce should be thick and fragrant. If warranted, cook another 5 minutes covered.

12. Once potatoes are tender, carefully remove and discard the foil covering from the gratin. Continue baking until cheese is golden, approximately 5 minutes.

13. Carefully remove gratin from the oven. Use a spatula or deep spoon to separate individual servings and serve while still warm.