Line a baking tray (approx. 35 x 40 cm) with baking paper. Warm milk and 1 tbsp. sugar lukewarm. Crumble yeast into it and dissolve it.
In a bowl, mix 250 g flour, 3 tablespoons sugar and 1 pinch of salt. Add yeast milk, 1 egg and fat and knead everything smooth with a hand mixer. Cover the dough and let it rise in a warm place for about 30 minutes.
Select the currants, wash them and remove them from the stalks. Coarsely grate the marzipan and pour into a tall mixing bowl. Add 1 egg and whisk smooth with the whisk of the hand mixer.
Knead the yeast dough again, roll out rectangularly (approx. 25 x 40 cm) on some flour. Spread thinly with marzipan paste, leaving an approx. 1 1/2 cm wide edge all around. Spread the berries on top.
Roll up the dough from the long side.
Cut the roll into about 12 slices. Clean the blade of the knife again and again and turn it in flour. Put the snails on the baking tray and let them rise for about 20 minutes. Bake in the preheated oven (electric cooker: 200°C/circulating air: 175°C/gas: level 3) for 15-20 minutes.
Mix icing sugar and 4-5 tablespoons of water. Take snails out of the oven and brush them with it. Cool down and let the icing dry.