This recipe will make you into the rock star of the kitchen. It is that good; we think it’s the best Potatoes Gratin recipe on the planet. Most people think they need to add cheese to make a gratin dish; this recipe shows them that they are wrong, way wrong. The cream with the slight bay flavor pairs just perfectly with the potatoes, and the thyme is just enough to add that little something. We really wish that we could give credit where credit is due, but, unfortunately, we’ve forgotten where we found this recipe.
Dec 5: This recipe came from In the Green Kitchen by Alice Waters.
Please, please, before you start making changes, try it just as it is.
- 3 Tbs unsalted butter
- 2 1/4 cups heavy cream
- 3/4 cup homemade vegetable stock (or liquid from rehydrating the mushrooms)
- 1 bay leaf
- 1 Tbs kosher salt
- 4 pounds medium-size Yukon Gold potatoes
- 1 Tbs chopped thyme
- Fresh-ground black pepper
- 2 drops liquid smoke (optional)
- 1 ounce dried Porcini mushrooms (optional)
Ingredient discussion: The stock is really there just to add a bit more liquid and not necessarily flavor. If you’ve saved the cooking liquids from various vegetables, you can use that. Or, as we’ll show, just use the liquid that is left over from rehydrating the Porcini mushrooms. Don’t try to substitute milk for the cream, nor half-and-half. Neither will propel you into kitchen rock stardom. If you can, use fresh thyme. And, be extra, extra careful if you use liquid smoke. You want just the slightest hint of a smoky taste; you’re not smoking fish here.
Rehydrate the mushrooms. If you’re using dried Porcini mushrooms, put them in a small bowl and cover with about a cup of boiling water. Let stand for about 45 minutes. Then drain, reserving the liquid, to use in place of the stock. Cut the mushrooms into small pieces. We use a pair of kitchen shears, which works nicely.
Preheat oven to 375°F.
Butter a 9x13x2-inch baking dish. If you have a gratin dish, use that; after all it’s made for gratins. We don’t have one, so we do what we can. When you butter the dish, use about 1 tablespoon of butter. A little more or less won’t matter.
Heat the cream. Put the cream, bay leaf, salt, stock or mushroom liquid, and liquid smoke, if using, in a medium pan and stir to combine. Bring the mixture to a simmer, reduce heat to low and let steep while you prepare the potatoes. Try not to taste it at this stage, but honestly, we always do.
Prepare the potatoes. Peel the potatoes, then cut into 1/8 inch thick slices. If you have one, use a mandolin (careful) or a food processor with a slicing blade. Otherwise, use a knife and try to make the slices uniform in thickness. Work quickly, but safely, so the potatoes don’t oxidize and turn brown. Do not put the potatoes in water; it will wash away the starches that make the gratin creamy. You don’t want potatoes in cream sauce, which, while good, is not a gratin.
Layer the potatoes. Place the potatoes in the baking dish, overlapping slightly, so it looks kind of like roof shingles. If you are using mushrooms, sprinkle pieces between each layer of potatoes. The potatoes you’ve sliced should make 3 to 4 layers.
Pour in the cream. Remove the bay leaf, and gently pour the cream over the potatoes. The cream will be just below the top layer of potatoes; when you press the potatoes down, the cream should flow over the top.
Dot with butter. You only used one tablespoon of butter for the pan, so the rest goes on top. Just cut the butter into small pieces and place each piece on top of the potatoes, trying to get them somewhat evenly distributed. Cover tightly with foil.
Bake until almost tender. Bake covered until the potatoes are almost tender, about 35 minutes. You should be able to pierce the potatoes moderately easily with a small sharp knife.
Increase the temperature to 400°F. Remove the foil, press the potatoes down with a spatula into an even thickness, allowing the creamy juices to baste the potatoes. Sprinkle the thyme and black pepper on top. Continue to bake, pressing the potatoes down periodically, until the gratin is nicely browned, about 30 minutes.
Let stand 5 minutes. Remove the gratin from the oven. It’ll be a little loose and creamy at this point; that’s okay, it’ll thicken a bit more while standing. After five minutes or so, the potatoes should have absorbed some more of the cream, and you’ll be ready to serve.
Serve and bask in your kitchen rock star glory. Heck, break out a glass of wine, if you indulge. You deserve it for dishes like this. I think once you taste this, you’ll know why it gets the five-star rating. And remember, keep this one for those special dinners when you really want to impress.