Then make the tangzhong. To a microwave-safe bowl add: 150g whole milk and 25g bread flour. Mix it up.
Put it in the microwave on full. Take the temperature once in a while; it needs to be at least 65°C/150°F.
Then mix it until it’s completely uniform.
Make the dough
Then it’s time to mix the dough.
To a medium bowl add: 550g bread flour, 30g sugar and 10g salt Mix it until it’s distributed.
Grab 220g ice cold whole milk. Add the melted butter and the tangzhong.
Make sure the temperature is below 35°C/95°F.
Then to the main dough add: 110g sourdough starter and 65g egg.
Then add the milk mixture to the top of the flour. Combine all the ingredients until you have a shaggy dough.
Then move everything to your counter and knead the dough.
Add more flour if needed to get a tacky but not sticky dough.
Shape the dough
Divide the dough into five equally sized pieces and shape each piece into a ball.
Then grab a rolling pin and a dough ball, roll it into a long oval, and roll it up tightly.
Roll that into a long strip using the rolling pin and roll it up tightly.
Continue with all the other dough balls until you have five little rolled logs.
Then grab a small Pullman loaf pan and spray the pan with baking spray.
Add the five rolls of dough and cover the pan with plastic wrap.
Proof the dough
Put the dough somewhere warm. I used my proofer set to 30°C/86°F.
Let it ferment until it’s about 2.5 cm/1 inch from the top.
Then turn on your oven to 180°C/350°F, or if you want, you can also put the dough in the fridge until you want to bake it. Then you should let it finish growing after you take it out.
So put the dough back in the proofer and let it rise to about 1.25 cm/½ inch from the top of the pan.
While waiting for the dough to finish fermenting, prepare an egg wash by combining an egg with a tablespoon of water.
Bake
Brush the dough lightly with egg wash, and put the bread in the oven.
Bake for about 45-50 minutes. The internal temperature should be about 95°Celsius/200°F.
Then remove the bread from the oven, and put it on a wire rack.
Take the bread out of the pan, and brush it with melted butter.