1. In a bowl combine sourdough starter and warm water until smooth

2. Add bread flour, sugar, and salt and mix until no dry flour remains

3. Cover and rest the dough 30 minutes for autolyse

4. Add melted butter and knead until fully incorporated

5. Cover and bulk ferment 4-5 hours at room temperature, performing three sets of stretch and folds every 45 minutes

6. Mix brown sugar and cinnamon for the filling

7. Turn dough onto floured surface and roll into a 9×12 inch rectangle

8. Spread softened butter over dough, sprinkle cinnamon sugar, then roll tightly from the short end

9. Place seam side down in a greased loaf pan and proof 2-3 hours until nearly risen to the top

10. Preheat oven to 375F (190C) and bake 35-40 minutes until golden brown and internal temperature reaches 195F

11. Cool on a wire rack at least 1 hour before slicing