Mix together 6 grams ripe, active sourdough starter with flour and water. Cover and set aside for 10-12 hours at 78-80ºF until doubled, bubbly active and peaked - just about to fall back down.Alternatively, ripe, active, bubbly sourdough starter can be substituted for levain in this recipe if that works better for your baking schedule.

Mix Ingredients: To a stand mixer (or a bowl if you are kneading by hand), add the ripe levain, warm milk, sugar, melted butter, salt, cornstarch and bread flour. Turn the mixer on and begin kneading the dough. If using cup measurements, reserve a little flour to add in during the kneading process - this keeps you from over-flouring your dough. Knead the dough for about 8 minutes in the stand mixer or 10-15 minutes by hand. Dough should be smooth, tacky but not overly sticky.

Bulk Fermentation: At this point the dough will be soft and cohesive. Dump the dough into a container and cover. Set the dough in a warm, 78-80ºF place for 4 hours. Take the temperature of the dough as needed to make sure it stays right around 78-80ºF. This temperature is optimal for fermentation. If your dough temperature is cooler than 78-80ºF, it will need to ferment longer than 4 hours.

Shape and Proof: Dump the dough out onto a (clean) countertop. Cut the dough into 12 equal-sized pieces. Take each piece of dough and pull/pinch up the sides until it forms a ball. Roll the ball on the counter using your hand in a cupping shape (see video here) to seal the balls and create tension for the roll to rise.

Nestle rolls together in an 8 or 9 inch baking pan. Cover the pan and let the rolls rise again for about 3-4 hours. During this time, I like to keep the rolls between 80-85ºF to encourage a little faster rise. If your temperature is warmer than this, the fermentation will go FASTER. If the temperature is colder than 78ºF, the fermentation will go SLOWER. I use a bread proofer to keep the temperature consistent.

Bake: Once the rolls have risen, doubled in size, are touching each other and soft, fluffy and airy, preheat oven to 350ºF. Bake the rolls in the pre-heated oven for 30 minutes until baked all the way through. The internal temperature of the rolls should register 190ºF.

Spread melted butter over the tops of the rolls and enjoy!