In blender or food processor, process peppercorns, thyme and bay leaf pieces until bay leaf is no longer visible and peppercorns are coarsely cracked. Sprinkle both sides of the chicken with salt, the pepper mixture, shallots and garlic, pressing lightly so seasonings cling. Cover with a clean sheet of waxed paper and let stand at room temperature for 2 hours. Discard garlic. Melt butter in skillet over medium high heat; until browned and cooked through. Remove to serving plate; sprinkle with chopped parsley. Add wine to pan drippings an cook over high heat stirring often, 2 minutes or until liquid is reduced to 3 tablespoons. Spoon over chicken breasts and garnish with parsley sprigs.