Although we think of a fruit curd as a preserve, it is more like a rich custard, in which the fruit juice effectively takes the place of milk, and butter adds richness. I use this lemon curd to fill tiny pâte sucrée tartlets, and serve them as petits fours.
200g (scant 1 cup) butter, diced
200g (1 cup) caster (superfine) sugar
grated zest and juice of 3 lemons
4 egg yolks
Put the butter, sugar and lemon zest and juice into a heatproof bowl. Stand the bowl over a saucepan of simmering water (making sure the base of the bowl isn’t in direct contact with the water). The butter will begin to melt after a few minutes. Whisk the mixture until it is completely smooth.
Add the egg yolks and whisk vigorously for about 10 minutes, until the mixture begins to thicken. Pour the lemon curd into a jar or small ramekins, cover with cling film (plastic wrap), and leave in the fridge.
Serve this divinely rich lemon curd straight from the jar or ramekins. Spread it like butter on toasted brioche or scones for a real treat.
For orange curd, substitute the lemons with 2 oranges and boil the juice to reduce by one-third before you start. I adore orange curd spread on Crêpes.