Herbed Potato Gratin (serves 10)
*Those of us who have made gratins, or have at least attempted them, know they are heavenly things, both visually and with regard to taste. Though a gratin is not something you can whip up in 30 minutes and is much more a labor of love, it is so fun and incredibly rewarding to make for a nice Sunday supper or a dinner entertaining friends or family.
4 large baking potatoes, peeled
1 medium onion or 2 small onions
2 garlic cloves, chopped
2 2/3 cups (2/3 pound) Gruyère Cheese (grated)
2 ¼ cups heavy cream
1 tablespoon chopped thyme
1 teaspoon chopped rosemary
2 tablespoons good olive oil
1 tablespoon unsalted butter (cut in half)
1 teaspoon kosher salt
¾ teaspoon freshly ground pepper
Preheat oven to 350°F. Use ½ tablespoon of unsalted butter to butter your baking dish (9x13, 9x14, or a large round and deep dish will work well). Heat the other ½ tablespoon of unsalted butter and 2 tablespoons olive oil in a pan. Slice the medium or 2 small onions thinly and sauté them on medium low heat, stirring occasionally, for 10 minutes. You want the onions to get tender but you do not want them to brown. If they start to brown just turn down the heat a bit and monitor them.
In a saucepan add the cream, thyme, rosemary, and chopped garlic. Warm cream on medium heat. Don’t let it boil, you just want it to get hot so you can infuse all of those wonderful herbs and the garlic into it, but you don’t need it to simmer or boil. Meanwhile, slice the potatoes thinly with a mandoline. If you don’t have a mandoline you can easily use a sharp knife and slice the potatoes by hand. A mandoline just speeds things up a bit and ensures an easy even cut (I’m not into a lot of “special equipment” in the kitchen but a mandoline pays for itself in convenience). Place the sliced potatoes in a large bowl. Once the onions are done, remove them from the heat. Remove the herb infused cream from the heat. If the cream has formed a skin at all, just skim it off of the top and discard the skimmed portion.
Add 2 cups of the grated Gruyère to the potatoes and give it a good stir. Add the sautéed onions to the potatoes. Separate 3 tablespoons of the herb cream and set aside in a small dish. Pour the rest of the cream over the potatoes. Sprinkle the potato mixture with 1 teaspoon kosher salt and ¾ teaspoon ground black pepper. Stir well. Pour the mixture into the baking dish and press down the potatoes (I do it with my hand to ensure it is smooth and even). Combine the 3 tablespoons of separated herb cream and 2/3 cup Gruyère and sprinkle it over the top of the potatoes. Bake 1 ½ hours until the gratin is browned and nice and bubbly. Let the gratin sit for15 minutes before serving.