Grate the lemon and save the juice for later. Heat the butter with milk. Mix egg, flour, butter, milk, sugar, lemon juice, dry yeast and flour to a smooth yeast dough.
Let the dough rise in a warm place for about 1 hour until doubled in volume.
For the snails, heat butter in a pan and toast the crumbs in it until golden brown.
Mix the butter crumbs well with lemon juice, sugar and cinnamon, knead the dough well again by hand and roll out into a rectangle.
Spread the crumb mixture on the dough, roll the dough tightly into a roll and cut into slices about 4 cm thick.
Place the pieces on a baking sheet and flatten slightly.
Whisk the egg and brush the snails with it. Bake in the oven at 180 °C top/bottom heat for approx. 15-20 minutes until light.
Decorate the snails as desired.