Brown Sugar and Mustard-Glazed Ham

Heat oven to 375 degrees F. Place the ham, cut-side down, on a rack set in a roasting pan. Score the ham. Add 1 cup water to the pan, cover the pan with foil and bake for 1 1 ⁄2 hours. Meanwhile, make the glaze: In a small bowl, combine the mustard, sugar and vinegar. Brush half the glaze over the ham and bake, uncovered, 20 minutes. Brush the remaining glaze over the ham and bake until the ham is heated through and its internal temperature registers 140 degrees F, 20 to 30 minutes more. During the last 20 minutes of cooking, make the mustard sauce. Place the white wine, shallot and sugar in a small saucepan and bring to a boil. Reduce heat and simmer until reduced by half, 3 to 4 minutes. Remove from heat and whisk in the mustards, sour cream and tarragon. Thinly slice the ham and serve with the mustard sauce.