Grease a 4 or 5 inch round pan with butter. Preheat oven to 180 degree centigrade. Melt the chocolate and butter together on the stove top or microwave until smooth.
Whisk in the sugar
Mix in the eggs, one by one.
Mix in the cocoa , vanilla and water until smooth.
Pour batter in the prepared pan. Bake for 25-30 minutes until a toothpick entered in the centre comes out clean.
Cool in the pan for 5 minutes and unmould carefully to cool completely on a wire rack.
Meanwhile prepare the sauce. Heat together the pomegranate juice (grind pomegranate seeds in a mixer and strain), sugar and lemon juice and bring to boil. Lower the heat and simmer until thick, for about 6-8 minutes. Let it cool.
Serve slices of cake with sauce served alongside or drizzle on the top.