Let the blueberries thaw in a pot. Bring 200 ml milk to the boil. Stir 1/2 sachet pudding powder, 1 tablespoon sugar and 5 tablespoons milk until smooth. Stir into the boiling milk, bring to the boil and simmer for about 1 minute.
Remove from the heat, pour into a bowl and cover with foil. Let the pudding cool down for at least 2 hours.
Slowly bring blueberries and 75 g sugar to the boil over medium heat. Stir 1/2 sachet pudding powder with 5 tbsp. water until smooth. Stir into the boiling berries, bring to the boil and simmer for about 1 minute.
Remove from the heat, pour into a bowl and cover with foil. Let the compote cool down for at least 2 hours.
Melt the butter. Add 200 ml of milk, warm up lukewarm. Mix yeast, 1 tablespoon sugar and 100 ml of the milk mixture. Mix flour, 1 pinch of salt and 100 g of sugar in a bowl, press a depression in the middle.
Pour yeast milk into the hollow, mix with some flour from the rim and cover with flour. Cover and leave to rise for about 15 minutes. Add the remaining milk mixture and egg and knead to a smooth dough using the dough hooks of the hand mixer.
Cover and leave to rise in a warm place for about 30 minutes.
Grease a baking tray (32 x 39 cm) and dust with flour. Roll out the dough rectangularly (approx. 35 x 45 cm) on a floured work surface. Mix the pudding with a whisk until smooth and spread it on the dough.
Add the compote and spread. Roll up the dough from the long side. Cut dough roll into approx. 20 slices. Place the slices next to each other on the prepared baking tray with the cut surface facing down.
Cover and leave to rise for about 15 minutes in a warm place.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 30 minutes. Remove and let cool on a cake rack. Caramelise 100 g sugar in a pan.
Add the almonds, stir and roast for about 2 minutes while stirring. Place on a baking tray lined with baking paper, spread and allow to cool.
Heat apple jelly in a pot. Spread snails with it. Break the brittle into pieces and spread on the snails. Serve with sour cream and blueberry puree.