Cranberry Casket Filled with Gold

Here is a truly spectacular finale to a festive meal. The pudding looks like a fantasy; a bright scarlet, crumpled flower with ragged petals, holding in its open bud something creamy, yellow and tempting. The scarlet case is, in fact, a cranberry sorbet and it is filled with a mango, lemon and rum ice cream. You can make this well ahead and eat it straight from the freezer.