For the Choux Pastry

1. Pre-heat oven to 425 F. (220 C.)
2. Combine water and butter in a saucepan and bring just to the boil.
3. Remove pan from the heat. In a separate bowl, sift together the flour, salt and sugar. In one go, add these dry ingredients to the water/butter mixture.
4. Over medium heat, stir with a wooden spoon until the mixture forms a dough and falls away from the sides of the pan. Remove from heat and let cool for 5 minutes.
5. Beginning with three eggs, beat in one egg at a time, stirring in each egg until the dough mixture is smooth and the egg is fully incorporated. After the third egg, the dough should be elastic and fall easily away from your spoon or spatula. If the dough is still a bit stiff, then add another ½ egg or another full egg until the dough reaches the right consistency; the dough should not be ‘runny’ like pancake batter but smooth and elastic.
6. Line a baking tray with parchment paper. Using a piping bag with a large tipped nozzle, pipe balls of dough onto the tray (spaced at least 2 inches apart), using about 2 tbsp. of dough for each ball. Pipe in concentric circles starting from the center and working outwards.
7. Place in the oven and bake for 10 minutes at 425 F (220 C), then lower the temperature to 375 F. (190 C.) for the remaining 10-15 minutes. The pastry balls will be done when they puff up and become golden. Each ball should feel light and airy.
8. Turn off oven and remove the tray from the oven; slit a small hole in the base of each pastry ball to release any steam. Return the tray to the oven for another few minutes to dry out the insides of the pastry puffs.

For the Custard Cream Filling

1. Warm the milk, cream and vanilla flavouring together over medium heat- do not boil.
2. In a separate bowl, whisk together the sugar and egg yolks for at least 30 seconds until the mixture becomes smooth and pale yellow in color, then add the flour.
3. Over medium heat, gradually whisk in the egg/sugar mixture to the milk/cream mixture. Continue whisking until the mixture thickens- if the custard is so thick that it will not pour easily, then add a little more milk or cream. Place in the fridge until chilled; the custard will continue to thicken some as it chills.
4. To fill each puff ball with custard, lift open the top of each pastry ball and fill with 1 -2 tbsp. of custard.

For the Chocolate Sauce

1. Over low heat, melt together the chocolate and butter. Mix in the cream and sugar and stir until the sauce is thick and smooth.
2. To serve, place one or two pastries on a plate and cover with chocolate sauce.