This recipe for chestnuts in soy caramel is courtesy of chef Matt Hoyle of restaurant Nobu 57.
Preheat oven to 450 degrees.
Place brown sugar and lemon juice in a large saucepan over medium-high heat, and cook, swirling occasionally, until darkened in color, about 10 minutes. Carefully add sake and soy sauce. Cook until thickened and syrupy, about 30 minutes.
Slit the skin of each chestnut with a large "X" to allow steam to escape as they cook. Spread 5 nuts evenly on a small baking sheet. Transfer to over and roast 15 minutes. Peel chestnuts immediately after roasting; cut in half and set aside. Repeat process with remaining chestnuts.
Line a nabe (a clay or cast iron Japanese pot) or a cast-iron skillet with an even layer of small, clean stones. Heat stones in oven until very hot, 5 to 10 minutes.
In a medium skillet, combine chestnuts and 6 tablespoons soy mixture. Cook until heated through. Remaining soy caramel may be refrigerated in an airtight container for another use, up to 2 weeks. Remove nabe from oven and spoon glazed chestnuts over heated stones. Serve immediately.