Add strong bread flour, caster sugar and yeast into a bowl and mix before adding the eggs. Turn the mixer on for 8 minutes on a medium speed and slowly add warm water as it mixes.
Add unsalted butter and allow it to mix for a further 8 minutes on a high speed.
Coat a bowl with some vegetable oil, place the dough inside and cover with cling film. Put it in the oven at 25 degree celsius for 3-6 hours.
Remove the cling film before working the dough to get rid of excess air and proof once again.
Put some flour on the kitchen worktop and knead the dough. Divide into 50g balls. Roll each ball in the flour until covered.
Grease two baking trays with cooking oil before placing the dough balls on the tray. Place a bit of oil on top of the dough balls and cover with cling film. Wait until they have doubled in size before proofing them in the oven for 20-30 minutes at 25 degrees celsius.
Take the trays out of the oven and remove the cling film carefully. Place a doughnut in a fryer filled with vegetable oil. Flip it over with a strainer (3 minutes on each side).
Take it out of the fryer after a total of 6 minutes, pat dry with kitchen roll and shake in a bowl of sugar.
Custard
Add 4 egg whites, 115g sugar, 30g flour, 455g of milk, and a vanilla pod seed into the mixer on 82 degrees heat for 10 minutes on a medium speed.
Put the mixture into a plastic bowl and cover with cling film before placing it in a bowl of ice and water to let it cool.
Then, when it is ready to use, remove the cling film and place the mixture into a piping bag. Use a filling nozzle to fill, if possible.
Meringue
Add 80g of egg whites into a mixer. Then, add a little water, and 180g of sugar into a saucepan and heat it up to 121 degrees. Then, add to the mixer that contains the egg whites, and mix for 5 minutes on a high speed until it has cooled down.
Dip the doughnut into the meringue, before using a blowtorch on them. Add a gold leaf as decoration.
