n an electric stand mixer fitted with the dough hook attachment, mix the buttermilk (or milk or water) and yeast and let sit for 15 minutes. Then add in the flour, melted butter, egg yolks, sugar, sea salt and cinnamon and knead on medium-high for about 15 minutes or until the dough ball becomes smooth. Swirl 1 tablespoon of oil around a large bowl. Set the dough inside, turning to coat completely with the oil. Cover the bowl tightly with plastic wrap and set in the fridge for at least 12 hours.