Buttery Sourdough Buns

Place the sourdough starter in the bowl of a stand mixer fixed with the dough hook attachment.In a small bowl, whisk the dry ingredients together.Add the dry ingredients, egg, butter and lukewarm water to the stand mixer and turn it on low speed. After a minute or two increase the speed to medium.Allow the mixture to kneed for several minutes until a smooth dough has formed.Place the dough in a lightly greased container and cover it with a towel or plastic wrap. Allow it to rise for 1½ - 2 hours, preferably in a warm, dark place (I use the attic or the laundry room on top of the dryer).Once the dough has roughly doubled in size, turn it out onto a clean, lightly greased work area. Gently punch down the dough and then roll it into a large rectangle.Combine the cocoa powder with 3 tablespoons of melted butter and brush it evenly onto the dough.Roll the long side of the rectangle evenly and tightly until you have one log. Using a bench scraper or knife, divide the log in half. Continue dividing evenly until there are 16 pieces.Place the buns swirl-side up into two greased cake pans, 8 buns per pan.Cover and allow to rise for an additional 60 minutes. Preheat the oven to 350 degrees F.Brush the buns with most of the remaining butter and allow them to bake for 22-25 minutes.Brush with the remaining butter and carefully turn out onto a cooling rack. Serve hot or warm.