Step 1Combine the wine and currant jelly in a small saucepan. Heat to a simmer. Reduce to 1/2 cup; this should take about 15 minutes. Reserve 2 tablespoons of the glaze for the sauce.
Step 1Heat the oven to 325 degrees. Lightly brush a roasting pan with olive oil.
Step 2Rub the cut side of the garlic halves all over the surface of the roast. Sprinkle the thyme, rosemary, marjoram and salt and pepper to taste over the meat and rub it into the meat. Place the roast in the pan crown side up. Cover the tips of the bones with foil to prevent burning.
Step 3Roast until a meat thermometer reaches 155 degrees, 15 to 20 minutes per pound. Brush with the glaze during the last 15 minutes of roasting. Remove the roast to a carving board; let stand about 15 minutes before carving.
Step 4Meanwhile, pour off the juices from the pan, about 1/2 cup, into a saucepan. Add the brandy to the roasting pan, stirring to loosen any browned bits from the bottom of the pan, then add to the pan juices. Stir in the reserved 2 tablespoons of the glaze. Bring to a simmer.
Step 5Combine the cornstarch and water until blended. Stir into the sauce and bring to a boil. Stir until slightly thickened and clear, about 2 minutes. Serve a tablespoon of sauce along with each serving of roast.