100gramseggs, 2 - 3 eggs, at room temperature, whisked together
INSTRUCTIONS
Chocolate Pastry Cream
Prepare a large bowl of ice water (enough to put a pot in). Set aside.
Combine 40 grams of sugar with the egg yolks in a large bowl. Whisk immediately with a wire whisk until the mixture is pale and smooth. Sift in the flour and whisk till smooth. Set aside.
Combine the milk, butter and the remaining 10 grams of sugar in a medium pot and warm over medium heat until it comes to a boil. Remove from heat.
Pour the hot milk, little by little, bit by bit, into the egg yolks, whisking constantly until 1/4 of the hot milk has been added. (Don't add the hot milk too fast, otherwise it'll scramble the eggs and you'll have to start over.)
After 1/4 of the hot milk has been added, add the hot milk in a slow and steady stream, whisking constantly - until 1/4 of hot milk is left. This whole process is called tempering.
Once the egg yolks have been tempered, pour the egg yolk mixture back into the pot and whisk to mix them altogether. Place the pot back on medium heat and with a wooden spoon, stir the mixture constantly until the mixture has thickened and has started to boil - you'll see huge air bubbles popping out of the custard - that's a sign that the pastry cream is ready.
Remove the pot from heat and place it in the bowl of ice water. Stir the pastry cream constantly until it has cooled down. Stir in the vanilla paste / extract and whisk in the cooled melted chocolate.
If using immediately, spoon the pastry cream into a piping bag and keep it refrigerated until needed. If not, transfer the pastry cream into a container, place a plastic wrap (cling film) directly onto the surface of the pastry cream (to prevent a skin from forming) and refrigerate for up to 3 days.
Choux
Preheat the oven to 200 degrees Celsius. Line baking sheets with baking parchment.
Sift flour and cocoa powder onto a large parchment paper.
Combine milk, butter, sugar and salt in a pot. The butter is softened and chopped to little pieces so that it melts fast during heating. Heat the mixture over high heat, stirring occasionally with a wooden spoon, and bring it to a rolling boil - the mixture should be boiling and bubbling vigorously until the layer of butter is no longer floating on top.
Working quickly, add in all the flour-cocoa at once, turn off the heat and stir quickly with the wooden spoon to mix in all the flour.
Once the flour has been mixed in, turn on the heat to medium-low and continue mixing with the wooden spoon (do not stop!) until the mixture forms a soft dough and that you can see a layer of dough at the bottom of the pot. Remove from heat and transfer the dough into a mixing bowl.
Using an electric mixer, mix the dough on low speed for 5 seconds, then add in the beaten eggs, a little at a time (I estimated one tablespoon each time). Make sure the dough has fully absorbed the eggs before adding more. The dough will first seemed to separate but will come together eventually into a thick, smooth and piping consistency - and that's choux pastry!
Transfer the choux into a piping bag fitted with a plain tip.
Pipe small mounds of equal-sized choux onto the baking sheets, about 1 inch in diameter, leaving 2 inches of spacing between each choux.
If you get little tips after piping, dampen your finger in a little water and flatten the tip of the choux to prevent it from getting burnt during baking. If desired, spray the surface of the choux with a little water immediately before baking - according to the chef, this helps the puff to expand even bigger during baking. (I've yet to try this, so not sure how true it is!)
Bake the puffs for 20 minutes at 200 degrees Celsius. Reduce the heat to 175 degrees Celsius and bake for another 20 - 25 minutes until the puff is golden brown and well-risen. During baking, no matter how excited you are, do not open the oven to check them as it will cause them to deflate and it'll be the worse thing to happen ever.
Turn off the oven, leave the oven door ajar and let the puffs cool in the oven for 30 minutes. Remove from oven and let them cool completely on a wire rack. (I usually place an oven mitten between the door and the oven to keep it ajar.)
Assembly
Once the puffs have cooled and ready to serve, pipe some pastry cream into the puffs and serve chilled, dusted with icing sugar. Store remaining filled puffs in the refrigerator for no more than 2 days as the skin will become soggy and soft.