There are few sights as uplifting in the kitchen as a golden, bubbling grating coming out of the oven. It's strange to be saying this, but one of the reasons I love this particular gratin is that it isn't too creamy and rich. And the relative thinness of the wine and milk the potatoes and mushrooms are cooked in - relative to heavy cream, that is - is what allows you to cook this in such a hot oven and so quickly.
The first two times I cooked this, I peeled the potatoes; now I don't bother. It isn't necessary (and I buy baking potatoes that come all clean and shiny) and even if peeling them doesn't really take long, it's a good psychological step to remove; this is now a quick slice and chop, in a pan and thence to the oven. It feels easy - but then it may be because it is easy.
- 3 average-sized (1-1/2 pounds) baking potatoes, thinly sliced
- 1-1/2 cups milk
- 3 tablespoons white wine
- Salt and pepper to taste
- 2 tablespoons butter
- 2 teaspoons garlic-infused oil
- 8 ounces cremini mushrooms, finely sliced to make 4 cups
1. Heat the oven to 425 F and butter a shallow baking dish or gratin.
2. Bring the sliced potatoes, milk, wine, salt, and pepper to a boil in a saucepan, stirring occasionally, and leave at a simmer while you get on with the mushrooms.
3. Melt the butter and garlic oil in a skillet over medium-high heat. Add the mushrooms and cook, stirring occasionally, until softened, about 3 minutes.
4. Pour the mushrooms and their garlicky, buttery juices into the pan of potatoes, stir to mix, and pour straight into the gratin dish. Bake for 45 minutes or until piping hot, and crisp on top.