Cherries Jubilee

In a small dish, combine a little cherry juice with sugar and cornstarch. In a skillet, heat juice from cherries over moderate heat. Add cornstarch mixture. When juice thickens, add cherries to warm through. Pour in warmed liqueur , then flame the pan to burn off alcohol . Remove cherries from heat. Scoop vanilla ice cream into large cocktail glasses or dessert dishes and spoon cherries down over ice cream .