Plan your sweet starter mixing time according to the baker's schedule (see notes), ensuring it has 8-10 hours to rise. Select a convenient time frame that aligns with your schedule.
In a small saucepan, heat the milk and butter up on low and allow to cool to room temperature.
Once cooled add the mixture to a mixing bowl and dissolve your sweet starter & the sugar in the mixture by mixing it with a fork.
Next, add your egg, flour, and salt. Mix with a silicone spatula for best results.
Cover with plastic wrap and let it rest for 30 minutes.
After 30 minutes, knead the dough into a smooth ball (8-10 minutes).
Place the dough in a generously coated buttered bowl, cover it with plastic wrap, and let it rest (8-10 hours).
Roll out the dough
When the dough is ready to be shaped, divide it into 3 equal balls. This is best achieved by weighing your dough. My dough was around 820 grams. Therefore, each dough ball was roughly 273 grams each.
Roll each dough ball into a 15x6-inch rectangle. Tip: lightly flour your rolling pin to avoid sticking.
Using a pastry brush, brush the dough with cooled melted butter. I find this helps the mixture spread better.
Make & spread the cinnamon roll filling
In a medium-sized mixing bowl, use your silicone spatula to mix the softened butter by itself. Once a creamy texture, add the cinnamon, sugar, and coconut sugar and mix well. Tip: add a teaspoon of melted butter to the mixture to help soften it a bitif needed.
Using your silicone spatula or spoon, begin to spread the mixture on the dough.
Shape the dough
Starting from the long side begin to roll the dough tightly, pressing down lightly on each roll. Once fully rolled, make sure the roll is seam-side down.
Using a pizza cutter or sharp knife, cut the dough down the center leaving an inch of dough still connected at the top.
Gently braid the two strands one over top of the other until you get to the end.
Then, bring the ends together and pinch them together to form a wreath.
Repeat with the remaining dough balls and place them on a lightly greased, parchment paper-lined baking sheet.
Cover loosely with oiled plastic wrap and allow the wreaths to rest for 1-2 hours or until puffed up.
Brush and Bake
Preheat oven to 350 degrees F and gently coat the wreaths with the egg wash (if you would like a softer dough you can skip the egg wash, however, you may not get that golden brown color).
Bake for 35-40 minutes or until lightly golden brown.
While the sourdough cinnamon swirl bread is cooling for about 5-10 minutes, make your glaze.
In a medium bowl whisk together the sifted powdered sugar, milk, & vanilla extract. Stir until combined, drizzle on your swirl bread, and enjoy!
These are best enjoyed the day of, but you can store them on your countertop in an airtight container for 2 days or up to a week in your refrigerator.
Notes
Baker’s schedule option 1:
Make the sweet stiff starter the morning of, and mix the dough in the evening (around 7 pm) to bake for the following morning.
Baker's schedule option 2:
Make the sweet stiff starter the evening before you mix the dough. Mix the dough in the morning, allow to proof, refrigerate overnight, and shape & bake the following morning.
Sweet starter: ensure your sweet starter has doubled in size before baking with it. *Any leftover sweet starter can be stored in an airtight container in the fridge for up to 1 week and used in various sweet discard recipes!