In a mixer, add the first 6 ingredients until well combined. Add the flour a cup at a time. Then add the softened butter, a tablespoon at a time.
The dough should clean the sides of the bowl and come together in a ball. It should not be too sticky. If it’s not quite there, add more flour one tablespoon at a time. Knead the dough for 10 minutes until the dough becomes stretchy and soft and can stretch into a windowpane.
Put the dough in a bowl somewhere warm until it has nearly doubled in size (depending on the temperature, this can take 6-10 hours). Refrigerate for 1-3 days for a long ferment.
On baking day, knead the dough several times to redistribute the yeast. Divide the dough into 9 pieces and roll into balls (3-3 1/4 oz balls). Place into an oiled 9x9 or 8x8 pan. Cover and let rise somewhere warm until light and fluffy and doubled (or more) in size.
Bake at 350° for 20-25 minutes and the rolls are golden brown. They’re fully baked if an inserted thermometer reads 200°. Brush melted butter over the tops of the rolls and serve!