Ingredients

1 pound Jerusalem artichokes, peeled and sliced 1/4-inch-thick and reserved in cold water until ready to use

3 cups milk

8 ounces creme fraiche

2 tablespoons freshly squeezed lemon juice

1 cup grated Gruyere cheese

1 tablespoon minced fresh thyme

1 teaspoon coarse salt

1/4 teaspoon freshly ground pepper

1/2 pound Yukon gold potatoes, peeled and sliced 1/4-inch-thick

5 ounces shallots, peeled and sliced thinly

5 ounces peeled chestnuts, halved lengthwise

4 slices white bread, lightly toasted, crusts removed, and torn into small bits (to make 1 to 1 1/4 cups)

Preparation

In a large saucepan, combine Jerusalem artichokes and milk. Bring to a boil, and reduce to a simmer, and cook for 10 minutes. Drain, reserving 3/4 cups of the milk.

Preheat oven to 450 degrees. In a medium bowl, whisk creme fraiche, reserved milk, lemon juice, 1/4 cup Gruyere, thyme, salt, and pepper. Add artichokes, potatoes, chestnuts, shallots; gently mix to combine. Transfer to a 6-cup shallow baking dish, and cover tightly with parchment-lined aluminum foil. Place on a rimmed baking sheet, and bake until artichokes are tender, about 1 hour. Remove foil, and sprinkle with breadcrumbs and remaining 3/4 cup cheese. Bake, uncovered, until golden brown, 8 to 10 minutes. Serve warm.