Step 1

Separate 4 large eggs into yolks and whites in two bowls. Warm 60g vegetable oil in the microwave for 40 seconds and set aside.

Step 2

Sift 40g all-purpose flour and 20g unsweetened cocoa powder into the bowl of oil. This ensures a smooth, lump-free batter.

Step 3

Add 60g sugar-free milk (room temperature) and 4 egg yolks to the dry mixture. Whisk until smooth and velvety.

Step 4

Gradually add 70g granulated sugar to the egg whites and beat until soft peaks form. The whites should hold their shape without collapsing.

Step 5

Add a small scoop of egg whites to the cocoa mixture to lighten it. Gently fold the rest of the egg whites into the batter without deflating it.

Step 6

Line a 15 x 15 x 7 cm square mold with parchment paper and wrap it in foil. Place the mold in a water bath with 80°C hot water filling halfway up the sides.

Step 7

Pour the batter into the mold and bake at 150°C for 50 minutes. The water bath ensures an even bake and prevents cracking.

Step 8

Remove the cake from the mold and peel off the parchment paper. Let it cool completely on a wire rack before slicing and enjoying.