Method

The following can be done in either a stand mixer with the dough hook attachment or in a large bowl with a fork.
Into the bowl, add the warm milk, yeast, caster sugar, eggs and egg yolk, vegetable oil, plain flour and salt. Turn the machine onto low and mix until the ingredients have come together and a sticky dough is formed, completely coming away from the bowl.
Turn out onto a floured surface, kneed for a couple of minutes until smooth and form into a ball. Place the dough into an oiled bowl and cover in clingfilm for 90 minutes until it’s doubled in size.
After 90 minutes, turn the dough out onto a floured surface. Cut the dough into quarters then each quarter into three. Working on one piece at a time, cut the piece of dough in half, and roll both halves out into two sausages, around 20cm long. Place one down horizontally, and the other, over the top vertically creating a cross. Then picking up the ends of the horizontal sausage, cross them over each other and place them back down. Repeat this with the vertical sausage, criss-crossing the pieces of dough to form a plait. Tuck the ends under the bun and place the braid onto a baking sheet lined with greaseproof paper. Repeat with the rest of the dough.
Cover the braided buns in cling film and allow to rest for another 30 minutes and preheat the oven to 170C/ 150C fan.
Uncover the buns. Mix together the egg yolk and milk and brush evenly over the buns. Scatter with sesame seeds and a sprinkle of seat salt.
Bake in the oven for 25-30 minutes or until a deep golden brown. Allow to cool a little before removing them from the baking sheet; but these are best served warm with salted butter.