Mix Dough: In a large bowl, combine 640 ml lukewarm water, 1 tablespoon yeast, 24 grams salt, 45 grams melted butter, 12 grams sugar, and 3 tablespoons bread booster (if using). Add 920 grams bread flour and stir until fully mixed into a wet dough.
Rise: Cover loosely and let the dough rise at room temperature for 2-4 hours or more if needed.
Refrigerate: (Optional but recommended) Refrigerate the dough so its easier to shape the buns. Dough can be refrigerated for up to a week. For the first two days, keep the lid slightly open to allow gases to escape.
Shape Rolls: Dust the dough with flour, cut off 80-90g pieces, shape into balls, then stretch into long rectangles. Roll tightly into buns and place on a parchment-lined baking sheet.
Preheat Oven: Preheat to 410°F (210°C) with a metal broiler tray on the bottom shelf.
Bake: Spray buns with water, slash the tops, and place in the oven. Add a cup of hot water to the broiler tray to create steam. Bake for 5 minutes, then remove the broiler tray and continue baking for another 25 minutes or until golden brown.
Cool: Let the buns cool completely on a rack before slicing/ eating. The buns will continue to bake as they cool outside of the oven. If you cut it while it is still hot the interior will be gummy.