Lemon Curd with vanilla

1/2 cup lemon juice 6 egg yolks 1 cup sugar 4 teaspoons freshly grated lemon zest 8 tablespoons cold unsalted butter , cut into pieces 1 To make lemon curd:[...]

170 g plain flour 1 1/2 teaspoons baking powder 70 g caster sugar 2 finely grated lemons , zest of 125 ml milk 1 egg , beaten 50 g butter , melted and cooled[...]