Instructions

1. 1
   Whisk the eggs and sugar together at high speed for 5 minutes using a stand mixer until the mixture expands into a thick, pale ribbon.
2. 2
   Gently fold the sifted flour into the egg mixture in three separate additions using a rubber spatula.
3. 3
   Stream the melted, cooled butter , lemon zest, and vanilla extract down the side of the bowl, folding carefully to incorporate without deflating the batter . Cover the batter tightly and refrigerate it for at least 1 hour (this thermal shock creates the iconic sponge hump).
4. 4
   Preheat your oven to 400°F (200°C).
5. 5
   Butter and flour a classic 12-shell madeleine pan.
6. 6
   Drop a tablespoon of chilled batter into each mold cavity.
7. 7
   Bake for 8 to 10 minutes until the madeleines develop their signature humps on top and the edges turn deep golden brown.
8. 8
   Unmold immediately.