Peel and core the apples, then grate them. Drain any excess juice and mix with sugar, lemon zest, or cinnamon.

Line an oven tray with baking paper and spread the apples in an even layer covering the entire surface.

Prepare the batter:

- Separate the egg whites from the yolks.

- Beat the egg whites until stiff peaks form using a mixer.

Beat the yolks and add the sugar (4 tablespoons), mixing until it turns pale and creamy.

Incorporate the flour and baking powder, mixing briefly with the mixer.

Gently fold the egg whites into the batter, mixing carefully.

Pour the batter into the tray, spreading it evenly over the apples.

Bake in a preheated oven at 200 degrees for 15-20 minutes.

The cake is done when it has a nice golden-brown color.

Flip the cake onto a kitchen towel so it appears paper side up.

Gently peel off the baking paper.

Begin rolling the cake carefully while it's still warm.

Roll it tightly and allow it to cool completely.

Slice gently with a knife. You can serve it warm, but it often tastes better chilled, allowing the flavors to meld beautifully. 

Enjoy!