Potato and Mushroom Gratin

Heat the oven to 425F and butter a shallow baking dish or gratin.

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.

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.

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 alongside the chicken or until piping hot, and crisp on top.