For Choux Dough:

1. Place milk and butter in a saucepan. Heat on a ‘medium-low’, letting the butter melt into the milk.
2. Bring the mixture to a boil. Add in 1 cup of flour and reduce the heat.
3. Whisk together for a while until a thick, lump-free mass forms. It should come off the sides of the pot relatively easily. Remove from the stove and leave to cool down.
4. Once completely cooled, beat in the eggs – one by one, mixing as you go. The dough should become smooth, a bit sticky and lump-free.  Divide the dough into two.
5. Grab a large rectangular cake tin (ideally 9 by 13 in / 23 by 33 cm). Grease it generously with butter and sprinkle with flour.
6. Spread one part of the dough on a cake tin and even out the surface with a butter knife or spatula. If the dough is sticky – don’t worry, that’s a good thing.
7. Bake at 390°F (200ºC) for 25-30 minutes, until the cake turns lightly golden. Do not open the oven while it bakes!
8. Remove to cool and repeat with another portion of the dough. Leave to cool.

For Vanilla Custard Cream:

1. Boil two cups of milk (0.5 litre) together with fine sugar and a packet of vanilla sugar.
2. Grab the remaining cup of cold milk (250 ml) and add an egg, 4 yolks, potato starch and regular all-purpose flour.
3. Bring to boil and continue cooking for 3 to 5 minutes – whisking continuously, until a lump-free custard forms. Once you’re happy with the texture, take it off the heat. Cover with cling film and leave to cool completely.
4. Place 3 sticks (340-350 g) of butter and two tablespoons of caster sugar in the bowl of your mixer. Blend together to form a light & fluffy butter mass. Gradually start adding custard, a few spoonfuls at a time, blending continuously.