Prepare the Levain (Night Before): Mix the sourdough starter, flour, and water (50 g each) in a bowl. Let it ferment for 10-12 hours at 78-80°F until bubbly and active.
Make the Dough (Morning): Mix the levain with the flour, water, and salt until a dough forms. Knead or stretch-and-fold the dough until smooth.
First Rise: Let the dough rise at room temperature for 3-4 hours or until it doubles in size.
Shape Rolls (Afternoon): Divide the dough into 12 equal pieces (about 65 g each). Shape each piece into a smooth ball. Arrange the rolls in a greased baking dish, leaving a little space between them.
Proof Rolls: Allow the rolls to proof at room temperature for 3-4 hours, or until they puff up and nearly double in size.
Bake the Rolls: Preheat the oven to 375°F (204°C). Bake the rolls for 25-30 minutes until golden brown, with an internal temperature of at least 190°F (88°C).
Finish with Butter: Brush the hot rolls with melted butter for a glossy finish. Cool on a wire rack before serving.