Melt the butter and let it cool down a little. Mix sugar and cinnamon. Roll out the dough, brush with butter. Sprinkle cinnamon mixture on top, except for 1 tablespoon. Roll up from the long side.
Cut into about 32 pieces. Place on 2 baking trays lined with baking paper. Whisk the egg and brush the snails with it. Sprinkle with remaining sugar mixture. Bake one after the other in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 12-15 minutes.