Place the pre-cooked chestnuts in a saucepan with the sugar and milk, cook until the milk is absorbed, then blend with a hand blender.
Add the cocoa powder and mix with a spatula. Pass the mixture through a potato masher directly into the serving bowls.
Whip the cream to form stiff peaks and decorate each bowl using a piping bag.
Top each serving with 2 or 3 Marron Glacés in Fabbri liqueur.