Preheat the oven to 170°C (340°F).
Separate the egg whites and yolks.
Add a pinch of salt and a few drops of lemon juice to the egg whites, then whisk until stiff peaks form.
Add oligosaccharide syrup and vanilla extract to the yolks and mix well.
Sift cocoa powder, almond flour, and baking powder into the yolk mixture and combine evenly.
Gently fold the meringue into the yolk batter in 2–3 additions.
Pour the batter into a chiffon cake mold and tap lightly to remove air bubbles.
Bake in the preheated oven for 25–30 minutes, then let cool completely before removing from the mold.