Rhubarb & Custard Doughnuts

To Make The Doughnuts 

1. Put all of the dough ingredients apart from the eggs and the butter into an electric mixer with a dough hook and mix.
2. With your mixer at a medium speed, add the eggs and allow them to become incorporated before pouring in the butter.
3. Beat the mixture for about 8 minutes until it starts to come away from the sides of the bowl and form a ball. Cover the bowl in cling film and leave it in a warm place to prove.
4. Be patient as you want it to double in size. This should take about 5–6 hours.
5. At this stage knock back the dough and give it a bit of a knead to squeeze out any extra air.
6. Put the dough back in the bowl, cover with cling film and leave to chill in the fridge overnight.
7. The next day, take the dough out of the fridge and cut it into 50g pieces. (You can freeze the pieces at this stage as long you keep them separate and in airtight containers and you can keep them in the freezer for up to 6 months.)
8. Roll the pieces into smooth, taut, round buns and place them on a baking tray lined with baking parchment, leaving space between them as they will grow in size and you don’t want them to stick together.
9. Cover in cling film and allow to prove in a warm place for about 3–4 hours until they have doubled in size. (When cooking the doughnuts from frozen leave them to prove for 6 hours at this stage.)

To Make The Crème Patissière

1. Pour the milk into a saucepan. Scrape the seeds out of the vanilla pod and add them to the milk. Heat the milk over a medium flame, but don’t let it boil.
2. Meanwhile mix together the flours and sugar in a large bowl and whisk in the egg yolks to form a smooth paste. Once the milk is warm, slowly pour it into the egg mixture, whisking as you go.
3. You will find that it quickly thickens. Once all the milk is incorporated you may want to pass it through a sieve to ensure that you have a really smooth, silky crème. Leave to cool completely. In a separate bowl, whisk the double cream until it is relatively stiff but not overwhipped. Mix this thoroughly into the cooled vanilla custard, until they are well combined.
4. Once the dough has risen for the second time you are ready to fry the doughnuts. Pour the oil into a heavy-based saucepan to just under halfway up the sides. Heat the oil to 170˚C, checking the temperature with a high-quality cooking thermometer.
5. Use a spatula to carefully remove the doughnuts from the baking tray, making sure you keep their nice round shape and that you don’t deflate them. Lower 4 or 5 at a time into the oil. Fry for about 4 minutes on each side until they puff up and bob on the surface of the oil.
6. Turn them over carefully with a metal spoon; you are aiming for a lovely even golden colour all over. These doughnuts benefit from being fried more slowly than you might expect.
7. Lay some kitchen paper on a baking tray and transfer the cooked doughnuts on to it to absorb any excess oil and to cool a little. Pour some caster sugar on to a plate and roll the doughnuts so they are covered in sugar. It’s best to do this when they are still warm as the sugar sticks to the doughnut better then.
8. Now you are ready to fill your doughnuts. Fill half with crème patissière, and half with rhubarb jam.
9. Fill two nozzled piping bags with the crème patissière and rhubarb jam respectively.
10. Use a sharp knife to make an incision into the centre of the doughnut, being careful not to pierce it all the way through. Insert the nozzle deep into the doughnut and firmly squeeze the bag to ensure that you inject a healthy amount of filling.