Preparation time: 10 minutes
Cooking time: 15-20 minutes
For 6 people or a standard cake tin
Preheat the oven to 180°C.
In a container, mix the flour with the salt, vanilla powder and cocoa powder (if desired).
Separately, whisk the egg with the brown sugar for a long time. Add the dry ingredients, including the hazelnut jam or spread, then the melted butter.
Pour into a mold previously lined with parchment paper and bake for about twenty minutes. The tip of a knife should come out still wet.
Enjoy warm or cold.