Preheat the oven to 325°F.
In a small mixing bowl, combine flour, baking soda and baking powder.
In a medium bowl, combine sugar, egg replacer mixture (or the egg and egg yolk), lemon zest, vanilla and butter.
Stir in the yogurt, lemon juice and flour mixture, mixing just until blended.
Using a tablespoon, fill pan cavities with a rounded tablespoon of batter. Bake for 12~14 minutes or until the madeleines are lightly browned.
Cool for 2 minutes and remove them onto a wire rack and cool completely.
Wash and prepare the pan; repeat with remaining batter. Dust with powdered sugar just before serving.