Make the Dough:
In a large mixing bowl, combine the sourdough starter, milk, eggs, sugar, and softened butter. Stir until smooth. Add the flour and salt, mixing until a rough dough forms. Knead the dough by hand or using a stand mixer for 8–10 minutes, until smooth and slightly tacky.

First Rise (Bulk Fermentation):
Cover the dough and let it rise at room temperature for 6–8 hours or until doubled in size. For best flavor, you can refrigerate it overnight after this step.

Shape the Rolls:
On a lightly floured surface, roll the dough into a rectangle about 12×16 inches. Spread the softened butter over the surface. Mix the brown sugar and cinnamon together, then sprinkle it evenly over the buttered dough. Roll the dough up tightly from the long edge into a log. Slice into 12 even rolls.

Second Rise:
Place rolls in a greased 9×13-inch baking dish, cover, and let rise for another 2–4 hours, or until puffy and nearly doubled. If using the overnight method, cover and refrigerate. Bring to room temperature for 1 hour before baking.

Bake:
Preheat oven to 350°F (175°C). Bake the rolls for 25–30 minutes, or until golden and cooked through.

Make the Glaze:
While the rolls bake, beat the cream cheese, butter, powdered sugar, milk, and vanilla until smooth and spreadable.

Glaze and Serve:
Let the rolls cool slightly before spreading the glaze over the top. Serve warm and enjoy every gooey bite!