Preheat oven to 425°F (220°C).

Whisk egg whites until stiff.

Gradually add vanilla essence, salt, and 1/3 cup sugar while whisking.

Stir in egg yolks one at a time.

Fold in flour, custard powder, and baking powder.

Transfer to a 12x15 inch baking tray lined with parchment paper.

Bake for 8-10 minutes.

Sprinkle a clean kitchen towel with sugar.

Remove sponge from oven and immediately turn it out onto the prepared towel.

Remove the parchment paper.

Roll up from the long edge and allow to cool.

Heat 2 tbsp sugar in a small frying pan.

Stir in the almonds and caramelize until golden.

Spread out onto a baking sheet lined with parchment paper.

Allow to cool and then chop.

Soak the gelatin powder according to package instructions.

In a bowl, mix remaining sugar, 5 oz coconut flakes, sour cream, and soaked gelatin.

Beat the whipping cream until stiff.

Fold the whipped cream into the sour cream mixture.

Carefully fold in the chopped almond brittle.

Unroll the sponge cake.

Spread 3/4 of the cream mixture over it.

Re-roll and refrigerate for 1 hour.

Remove from the fridge after 1 hour.

Cover with the remaining cream.

Sprinkle with the remaining coconut flakes.