Sunchoke Gratin with Jarlsberg, Lentils & Black Walnuts is an unexpected combination brought together in classic style.
Make Ahead The gratin can be prepared through Step 3 and refrigerated overnight. Bring to room temperature before baking.
- ½ cup dried green lentils
- 1 pinch kosher salt (plus more as needed for boiling and seasoning)
- ¼ cup chopped black walnuts
- 1 ½ pound sunchokes (also called Jerusalem artichokes)
- 1 cup heavy cream
- 1 ½ ounce Jarlsberg cheese (grated)
- 1 teaspoon finely grated lemon zest
- 2 clove garlic (minced)
- 1 cup fresh bread crumbs
- 2 tablespoon melted butter (plus more for baking dish)
Preheat the oven to 350 degrees F.
In a medium saucepan cover the lentils with about 1‑inch water and bring to a boil. Cover partially and cook over low heat for 10 minutes, stirring occasionally. Add a pinch of salt and cook until barely tender, about 5 minutes longer. Drain the lentils and spread them on a large baking sheet to cool quickly.
Spread the black walnuts on a baking sheet and roast for 10 minutes, or until lightly toasted. Transfer the black walnuts to a paper towel and let cool.
Bring a large pot of salted water to a boil. Meanwhile, slice the Jerusalem artichokes crosswise 1/8 inch thick. Add them to the boiling salted water to cook the slices until tender-crisp, about 5 minutes. Drain thoroughly and transfer to a large bowl. Add the cooked lentils, walnuts, cream, cheese, lemon zest and garlic, season with salt and pepper; toss gently. Butter the bottom and sides of a 5 or 6 cup oval baking dish or equivalent. Transfer the Jerusalem artichoke mixture and all its liquid to the buttered dish.
In a medium bowl, toss the breadcrumbs with the melted butter and scatter over the gratin. Bake for 30 minutes, or until the gratin is bubbling and golden brown. Let stand at room temperature for 15 minutes, then sprinkle with the parsley and serve.