Do the same with the other half of the dough, and bake in an already heated oven (180° centigrade) for 20 minutes. Leave the snakes to cool perfectly, and take them out only when completely cold.
Then prepare the glacings. Put the bitter chocolate in pieces in a little pot with the sugar and water. Have a soft kitchen brush ready. When the chocolate is melted and still very hot, brush with it the 2 snakes, then wait for the chocolate on the cakes to solidify.
Prepare the white glacing with the half egg white and fine sugar (beat the compound until it is like snow). Wash the brush and dry it, then with the white glacing draw on the snakes the design of a spine.