Put two-thirds of the lemon curd into a large bowl with the zest and cream, then beat with an electric whisk until it just holds its shape. Dribble over the rest of the lemon curd and divide between 6 small glass pots or glasses, marbling the curd through as you go. Sit the pots on a small tray, cover the whole lot with cling film and freeze for 30-40 minutes.
Put the biscuits in a strong plastic bag and bash with the end of a rolling pin to crumbs. When you’re ready for pudding, remove the pots from the freezer (they should be ice cold but still soft and creamy), top with crumbs and serve.
Make aheadYou can make thse ahead of time, just store in the fridge and transfer to the freezer roughly 1-1½ hours before you plan to eat them.