Melt the chocolate. Heat 3/4 cup (200 ml) of heavy cream. Pour the cream over the chocolate in three additions, mixing between each. Add 1 cup (250 ml) of cold cream, mix, then refrigerate for 2 hours.

In a large bowl, whisk the eggs with the sugar. Add the water and melted butter, and mix. Add half the flour and mix. Add half the milk while whisking. Then add the remaining flour and milk, and mix well. Grease your crêpe pan, pour in some batter with a ladle, and cook for about 1 1/2 minutes on one side and 30 seconds on the other. Repeat until all the batter is used.

Whip the ganache on medium speed until it thickens.

Place one crêpe on your serving platter. Spread a thin layer of ganache. Top with another crêpe and spread another thin layer of ganache. Repeat until all the crêpes are used.

Place the remaining ganache in a piping bag fitted with a star tip and decorate your cake.