Blitz the 200g digestive biscuits in a food processor to turn into fine crumbs. Add together with the 100g melted unsalted butter and blitz until combined. Divide the biscuit mixture among the bowls, and tap down with the back of a spoon to compress it and help firm it up.

Place the 600ml double cream and 150g sugar into a large pan over a low heat and bring to the boil slowly. Boil for three minutes, then remove from the heat and allow to cool. Add the lemon juice and zest and whisk well, and then carefully pour on top of the biscuit base. Let chill in the fridge for at least 3-4 hours until firm.