cElleriac is a vegetable dumpling. With its hint of anise and its raw texture, this root can be divisive, but when cooked, it takes on irresistible sweetness and a distinctly velvety texture. Love it in this seasonal gratin that’s enriched with mushrooms, garlic, melted onions, and delicious potatoes. It’s like drowning in an autumn bath, and just needs a crunchy salad on the side.
Celery, Potato and Mushroom Gratin
Adding mushrooms to the winning combination of celery and potatoes transforms this from a side dish into a main dish. If you are a meat eater, try frying some pancetta at the same time as the mushrooms.
to equip 25 minutes
cook 1 hour 30 minutes
2-3 medium celery (about 500 g), peeled, soaked and cut into quarters
3 medium potatoes (about 600g) peeled
80 grams butter
400 gm chestnut mushroomssliced
1 handful zaatar twigsselect
Salt and black pepper
4 garlic clovesPeeled and finely chopped
250 ml double cream
500 ml chicken or vegetable broth
2 large onionspeeled and chopped
75g grana Padano or Parmesan cheesegrated
Using a mandolin, cut the celery and potatoes into 3mm thick slices, and place them in a bowl of cold water with a squeeze of lemon juice while you prepare the other ingredients.
Place a large skillet over medium-high heat, and when hot, add half the amount of butter, mushrooms, and half the thyme, season generously and fry, stirring regularly, for five minutes. Add half of the garlic and sauté for another six to seven minutes, until the mushrooms erupt from the liquid and are golden, then remove from the heat.
Preheat oven to 220°C (200°C fan) / 425°F / Gas 7. Whip cream and broth in a bowl. Drain the celery and potatoes, then arrange a layer of them in the base of a deep, oven-proof dish. Top with half the onion slices and half the mushroom mixture, put a third of the remaining butter and a light sprinkle of cheese, and season generously with salt, pepper and grated nutmeg. Repeat for another layer of root vegetables, followed by onions, mushrooms, garlic, butter, cheese and spices, and then a final layer of potatoes and celery. Put the last amount of butter, then pour the stock and cream on top.
Squeeze everything into the liquid, sprinkle with the last part of the cheese and bake for 65-75 minutes, until golden, and the root vegetables are cooked to the tip of a knife.
Serve with a crunchy salad, some veggies, or with roasted pork chops or sausage.
This gentle gratin is also a good style for boulangerie—that is, no cream and just stock, which works well for vegetarians. Use oil instead of butter, skip the cheese and coat the gratin with some breadcrumbs instead.