1. Combine the eggs and caster sugar in a bowl and stir until pale
2. Add a few drops of vanilla extract, then sift in the low powder and stir evenly
3. Boil the milk until it boils, pour it into the batter and mix well
4. Put it on the fire and continue to heat, low fire, keep stirring during the period to prevent sticking to the pan, until the batter becomes a thick paste
5. Add butter while it is hot, mix well, cover or cover with plastic wrap, let cool
6. Because you are making puffs, you can cool the sauce directly into a disposable piping bag for later use, which is convenient and sanitary
