1/2 cup sugar
Zest of 1 lemon
1/2 cup freshly squeezed lemon juice
7 large egg yolks
1/2 cup butter, diced
In a bowl, whisk together the sugar, lemon zest, lemon juice and egg yolks.
Place the bowl over simmering water and cook, whisking occasionally, until mixture becomes really thick.
Remove from the heat and strain through a fine-mesh sieve. Set aside and let cool to just warm.
Gradually add the diced butter and whisk it in until completely incorporated. Strain again to avoid any lumps.
Place plastic wrap directly at the surface of the curd to prevent formation of a skin and let cool completely before using.
Inspired by "Miette"