Make the Cake Batter

1. Melt the butter in a saucepan.  Let it cool completely before using.
2. Rub the lemon zest into the sugar to release the natural oils for 1 – 2 minutes.
3. In a medium mixing bowl, whisk the eggs and lemon-infused sugar using a handheld mixer at medium speed until pale and almost triple in volume.  It takes around 6 – 8 minutes.
4. Place a sieve on top of the mixing bowl, sift in the flour, baking powder and salt.  Gently mix until well combined.
5. With the mixer running, slowly pour in the cooled melted butter into the mixture and continue to beat until well incorporated.
6. Cover the bowl with cling film and refrigerate for 24 hours.

Bake the Madeleines

1. Preheat the oven to 200℃ fan.
2. Grease the madeleine pan with melted butter, even though your pan is a non-stick one.  If you are not using a non-stick pan, grease the pan with butter and dust the wells lightly with flour.
3. Remove the batter from the fridge. Using a spatula, mix to loosen the batter.
4. Transfer the batter into a piping bag and cut a 25 mm hole of a piping bag.  Pipe the batter into the moulds around 80% full. You can also alternatively spoon the batter into the moulds.
5. Place the filled madeleine pan into the preheated oven and bake for 8 minutes, or until the cakes are puffed up and the edges are golden.
6.  While they’re still warm, or as soon as you can handle the heat, gently remove the madeleines from the pan and gently transfer them to a wire rack to cool completely.

Make the Glaze (Optional)

1. Start by adding 1 tablespoon of lemon juice and mix well until fully absorbed.
2. Continue adding lemon juice little by little, mixing in between, until you reach the right consistency.
3. The glaze should be thick, glossy, and slowly fall off the spatula—it should hold its shape when piped but still be smooth.

Decorate the Madeleines (Optional)

1. Make sure the madeleines are completely cool before decorating.
2. Place a sheet of parchment paper underneath to catch any dripping glaze for easy cleanup.
3. Transfer the glaze into a piping bag for more control, or use a spoon if preferred.
4. Pipe thin lines diagonally of glaze over each madeleine, or decorate as desired. You can also dip them into the glaze or brush a light layer on top for a simpler finish.
5. While the glaze is still wet, sprinkle a little lemon zest on top for a fresh, aromatic garnish.
6. Let the glaze set at room temperature—it will set within about 30 minutes on the countertop.
7. Serve with a cup of tea or coffee. Warning: one is never enough.