Trim all fat and connective tissue from lamb. Stir garlic, mustard seeds, 1 tablespoon dry mustard, Dijon mustard, salt and pepper in bowl to form paste. Spread half of paste over 1 side of lamb. Place piece of plastic wrap large enough to cover lamb in baking dish. Place lamb atop plastic wrap, paste side down. Spread remaining paste over second side of lamb. Gather plastic around lamb, covering completely. Chill overnight. Combine wine, beef stock, chicken broth and shallots in large saucepan. Boil until liquid is reduced to generous 1 cup, about 45 minutes. (Sauce can be made 1 day ahead. Cover and chill.) Preheat oven to 375F. Remove plastic from lamb. Place lamb on rack in roasting pan. Sprinkle with additional dry mustard, salt and pepper. Roast until thermometer inserted into thickest part of lamb registers 125F., about 1 hour 30 minutes. Place on platter. Add sauce to pan. Bring to boil, scraping up any browned bits. Garnish lamb with parsley; carve at the table. Pass sauce separately. Serves 6. Bon Appetit April 1995 Per serving: 183 Calories (kcal); 10g Total Fat; (37% calories from fat); 22g Protein; 16g Carbohydrate; 20mg Cholesterol; 2391mg Sodium Food Exchanges: 0 Grain(Starch); 2 1/2 Lean Meat; 2 Vegetable; 0 Fruit; 1/2 Fat; 0 Other Carbohydrates Converted by MM_Buster v2.0n.