1. Take the butter out of the fridge and let it sit at room temperature for about 1 hour before using, so that it will become soft enough to spread.
113 g Butter
2. In a large bowl, combine the milk, eggs, honey, and sourdough starter. Mix until well combined.
115 g Milk
3 Eggs
30 g Honey
150 g Active Sourdough Starter
3. Stir in the flour and salt, then mix until a dough forms.
500 g Bread Flour
10 g Salt
4. Turn the dough onto a lightly floured surface. Knead for 10 minutes, or until smooth and elastic. Add more flour or milk if necessary. Cover and let rest for 30 minutes.
5. Add the butter in two stages. Add half of the butter and knead until well incorporated. The dough may fall apart, but it will become smooth once the butter is incorporated. A dough scraper can be helpful in this step. Cover the dough and let it rest for 15 minutes.
6. Add the rest of the butter, and knead until the dough is smooth and elastic. Cover the dough, and let it rest for 15 minutes at room temperature.
7. To know if your dough is ready for the next step, perform the windowpane test. Stretch a small piece of dough until it is thin enough to see light through it. If it stretches without tearing, it is ready for the next step. If the dough tears, it needs to be kneaded more. Knead it for a few more minutes, then let it rest for 5 minutes and repeat the test. Continue kneading and resting until the dough is ready.
8. Bulk fermentation*: Transfer the dough to a greased bowl, cover it, and let it rise in a warm place until doubled in size. This could take anywhere from 4 to 12 hours, depending on the room temperature.
9. Chill the dough for at least 1 hour for easier shaping. It can be refrigerated for up to 24 hours.
I leave mine overnight.
10. Divide the dough into 7 equal pieces. Shape each piece into a ball by cupping your hand tightly over the dough and rolling it in a circular motion. If the dough is sticky, lightly flour the work surface.
11. Line the baking pan with parchment paper. Place the dough balls on the prepared pan and gently press down on them to create a better bun shape after baking.
12. Proofing*: Cover with plastic wrap or a tea towel and let them rise in a warm place for 2 to 4 hours, or until soft and light to the touch.
13. Preheat the oven to 350°F / 180°C.
14. Mix one egg and one tablespoon of water to make an egg wash. Brush the tops of the buns with the egg wash and sprinkle sesame seeds on top.
15. Bake for 35 minutes, or until the buns are golden brown and the internal temperature reaches at least 190°F / 88°C.
16. Allow the buns to cool completely before slicing them.
Enjoy!