Crust: In a standing mixer, combine butter, vanilla, confectioners' sugar, cake flour, salt. Wrap and chill dough until manageable. Roll out and transfer into tart pans. Pierce dough with fork and bake in a preheated 375 degree F oven for 10 to 12 minutes or until golden brown.
Curd: In a saucepan melt butter and add lemon juice. In a bowl combine eggs and sugar. Add some of the melted butter into egg mixture, then transfer all back to the butter. Cook over medium heat until thickened. Be careful not to overcook. Strain into bowl over an ice bath ? let cool. Pour into cooled baked tart shell. Chill for 5 to 6 hours.