1. In a large mixing bowl, whisk together the active sourdough starter, warm milk, granulated sugar, room temperature egg, and melted and cooled butter. Ensure the milk isn’t too hot, as it can kill the yeast in your starter.

2. Stir in the salt and 3 1/2 cups of all-purpose flour. If you’re using instant yeast for a faster rise, add it now. Mix with a wooden spoon or your hands until a shaggy dough forms.

3. Turn the dough out onto a lightly floured surface. Knead for 8-10 minutes, adding more flour a tablespoon at a time if the dough is too sticky, until it’s smooth and elastic. It should pass the “windowpane test” (you can stretch a small piece thin enough to see light through it without tearing).

4. Place the dough in a lightly oiled bowl, turning once to coat. Cover the bowl with plastic wrap or a clean kitchen towel. Let it rise in a warm spot until doubled in size. This will take 2-4 hours if using instant yeast, or 6-12 hours if relying solely on your sourdough starter.

5. Gently punch down the risen dough to release the air. Divide the dough into 12-16 equal pieces, depending on your desired roll size. Roll each piece into a smooth, tight ball. Arrange the shaped rolls in a greased 9×13 inch baking dish, leaving a little space between them.

6. Cover the baking dish again and let the rolls rise in a warm spot for another 1-2 hours, or until they are puffy and nearly doubled in size. They should look soft and pillowy.

7. Preheat your oven to 375 F (190 C). Bake the rolls for 18-22 minutes, or until they are golden brown on top and cooked through. If they start to brown too quickly, you can loosely tent them with foil.

8. Once baked, remove the rolls from the oven. Immediately brush the tops with 2 tablespoons of melted butter for a soft crust and extra flavor. Let them cool slightly in the pan before serving warm.