To make the lamb: Preheat the oven to 400 degrees F.

Season the lamb on both sides with salt and pepper. Heat a large Dutch oven over high heat, add the lamb, and sear on all sides until golden brown. Transfer the pan to the oven and roast for about 12 minutes for medium-rare. Allow to rest before carving into individual chops.

To make the vinegar: In a small saucepan, combine the vinegar, mint, and sugar and bring to a boil. Remove from heat and allow to cool to room temperature. Pour the vinegar mixture over the vegetables in a small bowl.

To make the celery root puree: In a small saucepan, cover the celery root with water and boil until tender. Strain the celery root, transfer to a food processor with the butter, salt and freshly ground black pepper, and puree until smooth. Keep warm.

To make the sauce: In a medium skillet, saute the shallots and garlic in 1 tablespoon butter until soft. Add the brandy and cook until reduced by about half. Add the hoisin and veal stock and bring to a boil. Lower the heat and simmer until reduced to a thick sauce. Add the remaining 2 tablespoons butter and whisk to combine. Season with salt and pepper, to taste.

To serve: Place a portion of the celery root puree in the middle of 4 plates. Strain the pickled vegetables and scatter around the puree. Arrange 2 lamb chops per plate on top of the puree and drizzle with the sauce.