1. Mix high-gluten flour, fine sugar, salt, yeast powder, egg whites, and milk, and stir into a slightly smooth dough with a bread machine.
2. Add unsalted butter and continue to knead with a bread machine to form a transparent film-like dough.
3. Put the dough into the container and cover with plastic wrap for basic fermentation for about 2 hours.
4. Poke a hole in the dough with your fingers and it will not bounce to prove that the dough has been fermented.
5. Divide the dough into 6 equal parts, cover with plastic wrap and relax for about 10 minutes after rounding.
6. Cut the cheddar cheese into thin slices.
7. Roll the dough into a rectangle with a length of 15 cm and a width of about 10 cm, and then spread the sausage and cheese slices after turning it over.
8. Roll into a cylinder with the interface facing down.
9. Use a knife to cut in the middle, but don't cut it off.
10. Turn the cut side up into two connected cylinders, put them in a finely spread baking pan, cover with plastic wrap, and leave for the final fermentation for about 25 minutes. Brush with egg mixture, put it in a preheated oven at 190ºC and bake for about 23 minutes.
