You 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.
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.