With whipped cream:
Make the chestnuts about 20 min in water. Now fold in the cooked chestnuts with whipped cream and arrange in a coupe (beaker). Garnish the chestnuts with whipped cream topping, sprinkle with either cocoa powder or powdered sugar at the end.
With milk:
Bring the cooked chestnuts to the table in hot milk, sweeten as desired and sprinkle with cocoa.