Preheat oven to 200c. Grease 2 large baking trays.
Place the butter and 150ml water in a heavy-based saucepan; bring to the boil over a medium heat. Quickly remove from heat and stir in the flour immediately. Return to a low heat and beat mixture with a wooden spoon until smooth. Remove from heat.
Gradually beat in the eggs, a little at a time, until mixture is smooth. Remove from heat.
Place mixture in a piping bag, fitted with a large smooth pipe, and pipe small rounds, well spaced, on the baking trays, or put headed teaspoons of the mixture on the trays.
Bake for 15 minutes . Change position of trays and bake at 190c for a further 10 minutes, or until crisp and golden.
Place on a wire cooling rack. Gently make cooling rack. Gently make a slit in the side of each and allow to cool.
Put the chocolate in a heat-proof bowl. Melt over a pan of barely simmering water until smooth. Alternatively, place chocolate in a microwave-safe bowl and melt in a microwave oven, on defrost, for two minute cycles until melted.
Cut each puff in half and fill generously with the cream. Dip each top in the melted chocolate and place on top of the filled puffs. Serve at once.
Recipe Notes
Sprinkle a little water over the baking trays after greasing. This creates steam in the oven and helps the choux puffs to rise.