For the groats, mix 4 tablespoons of currant nectar and starch until smooth. Boil up the rest of the nectar, half of the frozen berries, 1 vanilla sugar and 2 tbsp. sugar in a pot. Stir in the starch, bring to the boil again and simmer for about 1 minute while stirring.
Fold in the rest of the frozen berries. Remove from the heat, allow to cool for about 30 minutes, stirring frequently.
Cut bread into small cubes. Heat butter in a large pan. Fry the bread cubes all around in it until golden brown. Sprinkle with brown sugar and allow to caramelize slightly while turning. Take out and let it cool down.
Beat the sour cream and cream with the whisks of the mixer until stiff, adding 3 vanilla sugar and 1 tablespoon of sugar.
Put bread in a large container. Mix orange juice and grappa and sprinkle bread with it. Spread sour cream on top, add berry gruel. Leave to soak for at least 45 minutes.