Ingredients:

  • 4 large eggs (approx. 200g), separated and room temperature
  • 150g granulated sugar
  • 125g unsalted butter, melted and cooled
  • 1 tsp vanilla paste or extract
  • 12g lemon zest (from 2 organic lemons)
  • 30ml fresh lemon juice (approx. 2 tbsp)
  • 115g all-purpose flour, sifted
  • 500ml whole milk, lukewarm (approx. 100°F/38°C)
  • 1g salt
  • 10g powdered sugar for dusting

Instructions:

  1. Preheat oven to 325°F (160°C). Grease an 8x8 inch (20x20 cm) square baking pan.
  2. Place the 4 egg whites and 4 yolks into two separate, clean bowls.
  3. Beat the 150g granulated sugar with the egg yolks until the mixture is pale and leaves a ribbon trail.
  4. Whisk in the 125g cooled melted butter, 1 tsp vanilla, 12g lemon zest, and 30ml lemon juice.
  5. Fold in the 115g sifted flour and 1g salt until no white streaks remain.
  6. Pour in the 500ml lukewarm milk in a thin stream while whisking.
  7. In the other bowl, beat the whites until they form stiff, glossy peaks that don't slump.
  8. Gently fold the whites into the batter using a spatula. Stop when you still see small white clouds floating on top.
  9. Pour into the pan and bake for 50 minutes until the top is golden and the center has a slight wobble.
  10. Let it cool completely in the pan for 3 hours, then dust with 10g powdered sugar.