1. In a stand mixer bowl combine sourdough starter, warm milk, and granulated sugar until smooth.

2. Add flour and salt and mix on low until a shaggy dough forms.

3. Add softened butter one tablespoon at a time and knead on medium speed until dough is soft and elastic, about 8–10 minutes.

4. Transfer dough to an oiled bowl, cover, and perform two stretch-and-folds during a 4–6 hour bulk fermentation at room temperature.

5. Refrigerate the dough overnight for cold fermentation and flavor development.

6. On the next day, let dough rest 15 minutes, roll into a 12×18 inch rectangle on a floured surface.

7. Brush dough with melted butter and sprinkle evenly with brown sugar and cinnamon.

8. Roll dough tightly into a log and slice into 12 equal rounds using a knife or bench scraper.

9. Prepare the sticky bun sauce by melting butter in a saucepan, stirring in brown sugar, cream, vanilla, and a pinch of salt until glossy.

10. Pour sauce into a greased 9×13 inch pan, scatter pecans over the sauce, and arrange dough rounds spiral side up.

11. Proof the buns for 2–3 hours in a warm spot until nearly doubled, then bake at 350°F (175°C) for 30–35 minutes until golden and bubbling.

12. Cool for 5–10 minutes, invert onto a serving platter, and serve warm.