For the sponge, add the flour and yeast in a bowl, mix, add the warm water and mix well. Cover and let it ferment for 30 to 60 minutes.
Instructions - Bread
For the bread, in a bowl/mixer, add flour, salt and sugar, mix. Add the sponge.
Start with 160g of cold water and mix at lowest speed for 5 minutes.
Mix now for 10 minutes, only this time to knead, on second speed.
Add the butter and mix on lowest speed for 5 minutes, until incorporated.
Increase the mixer speed for another 10 minutes to finish the beating until it separates from the bowl.
Cover with plastic wrap or a damp cloth to ferment, leave it for 60 minutes.
Divide the dough into 6 equal pieces and place them on the oiled baking sheet, leave it for 60 minutes.
When there are 30 minutes left to finish the fermentation, turn the oven on to 250 °C with heat only on the bottom and pour boiling water in a tray at the bottom.
Place the buns on the highest shelf and spray water below the pan.
After 15 minutes, remove the tray with water to cut the steam.
