1.Choux: Pre-heat the oven to 200o C. Pour water into a small pot, add butter and salt and bring to boil.
2.Remove the pot from heat and add the sifted cake flour. With a spatula, work together the whole mixture till combined.
3.Turn on medium heat and continue working quickly the mixture till you see there is a thin layer at the bottom of the pot.
4.Turn off heat and transfer the mixture into a bowl, spread the mixture with spatula to make it become warm quickly (about 3 mins).
5.Add beaten eggs one by one into the warm mixture and stir quickly (to prevent cooking the egg) with the spatula until the mixture becomes smooth.
6.Well-done! Now, divide the mixture into 12 small balls about 2 cm each (with 2 table spoons or using pastry bag) and place them orderly on a tray with parchment paper.
7.Spray water to moisture them, then place the tray into the oven and bake for 25-30 mins until golden brown.
8.Cut them with a knife to release steam and if they are still soft inside, place them back in without turning on the oven for about 5 mins.
Pastry cream: Whisk the yolks, sugar together in a bowl until blended (about 3 mins). Add milk, coconut milk and corn starch into then mix again until well-blended.
10.Pour the mixture through a sieve into a small pot and boil in medium-low heat while whisking all the time until thickened and smooth.
11.Turn off heat, add butter, vanilla extract and a pinch of salt then stir the cream mixture again. Pour the pastry cream into a bowl and let cool. Remember to cover with cling film to prevent skin forming.
12.Finishing the dish: Cut, fill each choux with plenty of pastry cream and dust with powder sugar (optional)