The softest sourdough cinnamon rolls, with the addition of pumpkin in the dough and lots of warming fall spices in the filling. Oh, and they're doused in icing, of course. These are quintessential fall and make for a really fun and festive breakfast or brunch!
In a large skillet, melt the butter over medium-low heat. Once melted, remove from heat and pour in the milk. You want it to be at what feels like a good bath water temperature before using.To the bowl of a stand mixer fitted with the paddle attachment, add the pumpkin puree, starter, sugar, and egg. Mix on medium speed until well combined. With the mixer running on low speed, slowly pour in the warm milk mixture. Add the flour, salt, and nutmeg and mix on low speed until a dough comes together - about 1 minute. Scrape down the sides of the bowl, cover, and rest for 30 minutes.Affix the dough hook to the stand mixer and mix on LOW speed (no higher than 2) for 6-8 minutes, until the dough begins to look smooth. (This is a very wet dough, but is also quite slick thanks to the butter. Don't worry if it looks too wet at this point - it will settle down after rising.) Turn the dough out onto a generously floured surface. Shape into a ball and place seam side-down in a large, buttered bowl. Cover, and let rise until doubled in size, about 8-12 hours.
For the Filling
Melt the butter in a small skillet or saucepan. Remove from heat and stir in the brown sugar, cinnamon, nutmeg, allspice, ginger, and cloves. It will be the texture of wet sand.
Shaping the Rolls + The Second Rise
Line a 9 by 13-inch baking dish with parchment paper that's been balled up and flattened a couple of times.Turn the dough out onto a generously floured surface. Press it into a flat disc and shape into a rough rectangle with your hands. Roll it into a 12 by 20-inch rectangle, adding more flour as needed so it doesn't stick to the rolling pin or the work surface.Sprinkle the spiced sugar filling over the dough, spreading evenly across the dough with your hands. Leave a 1-inch strip at one of the longer ends uncovered by filling. Starting at the opposite long end, begin rolling the dough into a log. Keep it as tight as you can. When all of the dough is rolled, pinch to seal. Use a bench scraper, knife, or unscented dental floss to cut (12) 1 ½-inch rolls. Place them in the prepared pan. Cover and let rest at room temperature for 1-4 hours, until significantly puffed up.
Baking the Rolls
When the rolls are nearing the end of their second rise (when they're starting to look nice and puffy!), preheat the oven to 350 degrees. Bake on the middle rack for 30-40 minutes, until cooked through to your liking. If you like cinnamon rolls gooey, check closer to the 30-minute mark. If you like them cooked through and brown, start checking at the 35-minute mark.Let the baked rolls cool for 10-15 minutes in the pan while you make the icing, then you can either keep them in the pan, or lift them out using the parchment paper.
For the Icing
Add the powdered sugar, milk, butter, and vanilla to the bowl of a stand mixer fitted with the whisk attachment. Mix - increasing the speed as the powdered sugar is incorporated - until the icing is smooth. Scrape down the sides of the bowl as needed. If the icing is too runny, add more sugar. If it's too stiff, add a splash more milk. Once the cinnamon rolls have rested 10-15 minutes, pour the icing over top. You want the cinnamon rolls to be warm, but not piping hot when you ice them - otherwise, the icing will melt straight to the bottom of the pan.Enjoy warm. Leftovers can be stored in an airtight container in the fridge for up to 5 days.
Notes
Making ahead: If you want warm cinnamon rolls in the morning without the hassle of getting up to do the shaping and baking, you can bake them and leave them covered with foil (once they've cooled) at room temperature. Make the icing too while you're at it and pop it in the fridge. Then reheat the rolls, still covered with foil, at 325 degrees for 15-20 minutes. Ice and enjoy!