• Beat eggs and sugars in a large bowl of an electric mixer for about 7 to 8 minutes, or until thick and creamy (Mixture should be tripled in volume). Beat in vanilla.
• Sift the flour and baking powder, twice onto a sheet of baking paper, then again over egg mixture. Add a pinch of salt and fold until just combined.
• Pour warm butter into a separate bowl and add about 1 cup of the egg mixture. Stir to combine, then add to the remaining egg mixture and gently fold until just combined. Cover surface with plastic wrap. Refrigerate for at least 3 hours, or overnight if time permits.
• Preheat the oven to 180C (fan-forced). Brush two x 12-hole madeleine pans generously with melted butter.
• Transfer chilled mixture to a disposable piping bag. Pipe (or spoon) among pan holes, filling about three-quarters of the way.
• Bake for 10 minutes, or until the edges golden brown and sponge bounces back when lightly touched. Remove pans from oven, then invert and tap the pans to release madeleines.
• Dust with icing sugar mixture to serve.

TIP: Ensure the butter is still warm when combining it with the batter to prevent it from solidifying and causing streaks. Try adding a teaspoon of finely grated lemon or orange zest to the batter for a citrus twist.