This is a set lemon curd, cooked the classic way with fresh lemon juice, sugar and whole eggs, then enriched with butter and given a little gelatine so it holds its shape once chilled. The gelatine is what separates it from a spreadable curd: it stays soft and creamy on the tongue but slices cleanly and will not slump against a sponge layer or run out of a tart shell.

The flavour is sharp and bright, balanced by the butter into something silky rather than tart alone. Use it to fill lemon tarts and pies, to layer between light sponges, as a filling under whipped cream or meringue, or piped into small pastry shells. It keeps well in the fridge for several days, which makes it a useful thing to have ready before you start assembling a cake.