The old dough refers to the leftover dough. I think it has the effect of making the texture more chewy. I didn't have any old dough, so I made it the day before using yogurt and strong flour, so I kept it at room temperature because it wasn't hot.

Remove the butter to room temperature to make the butter filling.

Mix all the ingredients, mix them so that the salt melts well, and put them in a piping bag.

Squeeze it into 9 pieces and harden it in the refrigerator.

Mix all the bread dough ingredients and knead for about 9 minutes.
If you don't have gravitational flour, you can use strong flour, and knead it for another 1 to 2 minutes.

This bread goes without the first fermentation.
Divide the dough into 80g pieces right away.
After rolling, let it rest for about 20 minutes.

Put the remaining dough in the freezer and use it as an old dough for the next bread.

Add butter inside the dough as if you're putting dumpling filling.

Seal the butter well so that it doesn't count.

Place butter filled dough in panning intervals and ferment for about an hour.

Make toppings while bread dough is fermented.

Mix coffee in room temperature butter, add sugar, and mix eggs two times. Mix milk and flour well to complete the dough.
Make sure to sift the flour and prepare it.
If there is a lump of sugar, put it down through a sieve.

Place the finished dough in a piping bag.

Preheat the oven to 160 degrees
Squeeze the topping over the bread dough.

Bake for 18 minutes in a 160-degree preheated oven.
Adjust the temperature according to your oven condition.

The mocha bun is done with a delicious smell.

The old dough refers to the leftover dough. I think it has the effect of making the texture more chewy. I didn't have any old dough, so I made it the day before using yogurt and strong flour, so I kept it at room temperature because it wasn't hot.