Combine the active sourdough starter, whole milk, sugar, and melted butter in a large bowl or the bowl of a stand mixer. Mix well. Add the flour and salt, stirring until a shaggy dough forms.
Knead the dough in the stand mixer for 4-5 minutes on medium speed or on a floured surface for 8–10 minutes until smooth and elastic.
Place the dough in a lightly oiled bowl, cover, and let it rise at room temperature for 10-12 hours or until doubled in size.
Punch down the dough and divide it into four equal pieces. Roll each piece into a circle approximately 10 inches in diameter. In a small bowl, melt the butter. In a separate bowl, mix together ½ cup of sugar with 2 tablespoons of cinnamon.
Place one circle on a parchment-lined baking sheet. Brush ⅓ of the melted butter onto the dough evenly across the surface, leaving a ½-inch border. Sprinkle with cinnamon and sugar.
Repeat the process for the rest of the dough and the rest of the cinnamon sugar mixture.
Place a small glass or jar in the center of the circle to mark the center. Using a sharp knife, cut the dough into 16 equal sections, leaving the center intact.
Take two sections that are next to each other, twist them outward two times. Pinch the ends together. Repeat with all sections. Cover the shaped bread and let it rise for 2-3 hours at room temperature.
Preheat your oven to 375°F . Brush the bread with egg wash for a golden finish. Bake for 35-40 minutes or until golden brown. Drizzle with icing or powdered sugar before serving!