01 -
Warm lemon juice and sugar in a saucepan over medium-low heat until sugar dissolves. In a separate bowl, whisk whole eggs and yolks until pale. Gradually whisk warm lemon mixture into eggs one tablespoon at a time. Return to saucepan and cook over low heat, whisking continuously until thickened to pudding-like consistency. Remove from heat, stir in butter, cover with plastic wrap touching surface, and refrigerate at least 1 hour.
02 -
Preheat oven to 350°F. Butter the madeleine pan thoroughly to prevent sticking.
03 -
Whisk eggs and sugar in a large bowl until pale and foamy. Gently fold in flour and baking soda. Add lemon zest, vanilla extract, and melted butter, mixing until smooth and thick. Chill batter in refrigerator for 15 minutes.
04 -
Spoon approximately 1 tablespoon of batter into each mold. Bake 9 to 10 minutes until edges turn golden and centers puff up. Remove and cool completely on a wire rack.
05 -
Fill a pastry bag with chilled lemon curd and pipe into the hollow of each madeleine until curd slightly oozes. Dust generously with powdered sugar before serving.