Panna Cotta with Grappa and Raspberries

• 1.2 litres/2 pints double cream
• 2 vanilla pods
• thinly pared rind of

Pour 900 ml/1½ pints of the cream into a pan, add the vanilla pods and lemon zest, bring to the boil, then simmer until reduced by one-third. Remove the cooked zest and set aside. Remove the vanilla pods a