Melt 60 g butter, add 175 ml milk and warm up. Mix flour, yeast, 60 g sugar, salt and lemon peel. Add the milk-butter mixture and mix with the dough hooks of the hand mixer. Add eggs and knead for about 2 minutes to a smooth dough.
Cover the dough and let it rise in a warm place for about 20 minutes.
Wash the blueberries, drain and mix with the jam. Roll out the dough to a rectangle (approx. 30 x 45 cm) on a work surface dusted with flour. Melt the rest of the butter.
Brush the dough with it and sprinkle with the remaining sugar. Spread the blueberry mixture on the dough. Leave a rim (approx. 2 cm). Roll up the dough from the long side to a "snail" and cut into approx. 15 slices.
Grease a pie mould (approx. 26 cm Ø). Place the slices of dough side by side in the mould and leave to rise for approx. 1 hour.
Bake the snails in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 25 minutes. Cover if necessary after approx. 20 minutes. For the glaze, stir 2 tsp. milk with lemon juice and icing sugar until smooth.
Let the yeast snails cool down on a cake rack for about 15 minutes. Spread the icing over it. Let it cool down.