Gale Gand S Grilled Buttermilk Bread Pudding With Rhubarb Pear Compote

½ cup orange juice 2 tablespoon honey 2 tablespoon light-bodied red wine ½ cup light brown sugar 1 vanilla bean, split and scraped (optional) 2 teaspoon cornstarch ½ teaspoon cinnamon 4 medium-ripe pears, seeded and cut into quarters 4 stalks rhubarb (washed, trimmed and cut into 1-inch sections) or one 8- to 10-oz. bag frozen rhubarb