Celeriac Potato Au Gratin
Recipe type: Side
Cuisine: French
Prep time: 
Cook time: 
Total time: 
Serves: 10-12
A flavorful, savory gratin made with Yukon gold potatoes and celeriac and topped with Gruyere.
  • 2 medium-sized celeriac (celery root)
  • 5 Yukon Gold Potatoes (or an all-purpose potato)
  • 4 cups half-and-half (or 3 cups heavy cream + 1 cup whole milk)
  • 1½ cups shredded Gruyere
  • Fresh or dried thyme
  • 1½ teaspoons salt
  • ¼ teaspoon fresh ground black pepper
  • 1 Tablespoon butter, for baking dish
  • 1 garlic clove, cut in half
  1. Preheat oven to 350°F.
  2. To prepare the celeriac - cut off both ends of the celeriac. Use a sharp paring knife to peel the tough outer skin. Just as you would with a potato, remove any dark pits or "eyes". Soak the celeriac in acidulated water--use 1-2 Tbsp. fresh lemon juice or white vinegar. The celeriac brown quickly when exposed to air. Cut each celeriac into ¼" slices. Place the sliced celeriac back in the acidulated water.
  3. Peel and slice the potatoes into ¼" slices.
  4. Place the sliced celeriac and potatoes in a large stockpot. Pour the half-and-half (or milk and cream) over the sliced vegetables. Add a good amount of freshly ground black pepper (1/2 tsp.) and salt (about 1-1/2 tsp.) Bring to a simmer over medium heat. Cook until the tip of a knife goes through the slices with a little resistance. (You do not want to cook the potatoes and celeriac until they are completely cooked.)
  5. In the meantime, rub the inside of a 9" by 13" glass pan with the garlic halves. Grease the bottom and sides of the pan with a generous amount of butter. Pour the partially cooked vegetables into the prepared pan. Sprinkle the top with the fresh or dried thyme. (I used dry because I was out of fresh--use a little less.) Top with grated Gruyere cheese. Bake for about 30-45 minutes or until the top is brown and bubbly. Let cool slightly before serving.
  6. Serve with roasted or broiled meats, like steak or pork tenderloin.
Recipe by Cafe Johnsonia at https://cafejohnsonia.com/2008/02/celeriac-potato-au-gratin.html