1-Preheat the oven: Preheat the oven to 325°F (160°C), standard or fan-forced, and butter an 8″ x 8″ (20cm x 20cm) square cake pan to prevent sticking.

2-Beat egg whites: Beat the egg whites until stiff peaks form; set them aside for later.

3-Beat egg yolks: Beat the egg yolks with the sugar until pale yellow, which takes about 1 minute, to build a solid base.

4-Add vanilla and butter: Add the vanilla extract and melted butter, then mix well for 30 seconds to 1 minute to blend the flavors.

5-Add flour: Add the flour and beat until just combined, keeping it light and airy.

6-Add milk: Slowly add the lukewarm milk while beating until everything is fully mixed, resulting in a thin batter like thick pouring cream.

7-Fold in egg whites: Gently fold in the beaten egg whites in three parts, preserving as much air as possible for that fluffy top layer.

8-Pour batter: Pour the batter into the prepared cake pan and smooth it out.

9-Bake cake: Bake for 40 to 50 minutes until the top is golden brown and the cake doesn’t jiggle when shaken. If it browns too quickly around 30 minutes, cover loosely with foil and bake in 10-minute increments.

10-Cool cake: Cool in the tin for 10 minutes, then invert onto a cooling rack and let it cool completely before serving.