- Preheat oven to 220degrees celsius.
- Boil water, butter, sugar and salt in a covered pot. Add in flour and cook 2 minutes, stirring.
- Transfer to a bowl and beat for a further 2 minutes.
- Beat eggs in one by one till each has incorporated well. Beat in egg white in the same manner.
- Place 1 tbsp of dough on a baking sheet, well spaced apart. Bake for 5 minutes.
- Reduce heat to 180 degrees celsius and bake for another 15mins.
- Remove, slit the puffs a little to let steam out and bake another 15 minutes Cool at a fan.
- Combine egg yolks, custard powder and sugar together with tbsp of the milk.
- In a pot, bring the rest of the milk to a simmer.Turn off heat.
- Pour milk in slowly to egg mix, whisking non stop. Return to heat and cook over low heat till thickened. Cool.
- Fill puffs with cooled custard.