Step 1: Preheat the oven

Preheat your oven to 190°C (375°F). Lightly grease the madeleine tray with melted butter and dust with flour to prevent sticking.

Step 2: Prepare the batter

In a mixing bowl, whisk the eggs and caster sugar together until pale and fluffy. Add the lemon zest, vanilla extract, and melted butter, whisking until fully combined.

Step 3: Fold in the flour

Sift the self-raising flour into the mixture and gently fold it in using a spatula until the batter is smooth. Be careful not to overmix.

Step 4: Chill the batter

Cover the bowl with cling film and chill the batter in the refrigerator for 20-30 minutes. This helps the madeleines achieve their signature hump.

Step 5: Fill the molds

Spoon a tablespoon of batter into each mold, filling it about three-quarters full. Smooth the tops slightly with the back of the spoon.

Step 6: Bake

Place the tray in the preheated oven and bake for 10-12 minutes, or until the madeleines are golden brown and springy to the touch.

Step 7: Cool and serve

Remove the tray from the oven and let the madeleines cool in the molds for a few minutes. Carefully transfer them to a wire rack to cool completely. Dust with icing sugar or dip in melted chocolate if desired.