For this light, delicate recipe, a portion of flour is cooked in advance and left overnight. It is then added to the remainder of the ingredients to make a light dough.
Make the Yudane at least 8 hours you want to use it. Put 50 gr bread flour into a saucepan add 40 ml water. Mix over a low heat until very thick (a couple of minutes). Let it cool. Put into a bowl, cover it and put in the fridge overnight.
Measure the bread flour, sugar, butter and yeast into the bowl of your stand mixer. Mix lightly then add the salt.
Add the milk and mix to combine all the ingredients. Then start mixing dough at a medium speed. Add the yudane torn into small piece into the dough. Knead until the dough comes away from the sides of the bowl (at least 10 minutes). It should measure between 24° and 26°C (75 to 78°F).
Cover the bowl and allow to prove for about 1 hour. It will rise well in this time. When pressed with a finger, the whole made will fill very slowly.
Cut the dough into two equal pieces and shape into balls. Let it rest for 10 minutes.
Roll out each pieces to about 15 x 20 cm with a rolling pin. Roll each piece up tightly, then roll a second time from the thinner end.
Place both pieces of dough next to each other in the tin.
Pre-heat your oven to 180°C/350°F
Cover the breads with a damp tea towel and allow to rise for 30 minutes. It should fill the tin. Brush with egg before baking.
Bake the bread for 25 to 30 minutes. Test to see whether with your digital thermometer. It should register over 95? (200?). It does brown easily so cover with baking parchment if it is browning very quickly.