Sift the cake flour. Beat the egg until smooth.
Put the ingredients into a pot and bring to a boil over high heat.
Add the flour and quickly mix together (work quickly).
Reduce the heat when it becomes opaque and transfer to a bowl. (This is so that the residual heat on the pan doesn't cook the egg.)
Add the egg a little at a time. Mix until the batter clinging to the spatula creates a triangle as it slowly plops down in slightly hardened lumps. (Please adjust the consistency until the batter looks like the picture).
Put half of the batter into a pastry bag and squeeze it out onto a baking sheet. Sprinkle with water from dampened hands. Bake at 200℃ for 10 minutes, then reduce the heat to 190℃ and bake for another 5 minutes.
Add the cocoa to the remaining batter and bake the same way as in Step 6.
Make the custard. Mix together the sifted flour, sugar, milk, and egg. Mix it up really well.
When it becomes fluffy, wrap with plastic and cook in the microwave for 2 minutes at a time until it becomes as thick as you'd like.
For the chocolate custard, break the chocolate up into small pieces and heat in the microwave at 600 W for 1 minute. Stir to melt. Add 1 1/2 to 2 tablespoons of the plain custard and mix.
They're full of custard! To fill without cutting them, poke a hole in the bottom and use a pastry bag to fill the puffs.
Here's the Halloween version! The orange is made with food coloring!!
Story Behind this Recipe
I wanted to eat a delicious cream puff that would get me excited about Valentine's Day.
It's best if you use room temperature milk to make the custard (cold milk is likely to cause lumps and unevenness).