Add 3 cups of flour and stir together with a spatula. Add additional flour until the dough comes together. Continue adding flour until the dough is soft but not sticky.
Place the dough in an oiled boil. Cover and let rise until increased in volume 30% to 50%. Please see the recipe notes. While the dough is rising, make the custard.
Over low heat, combine the cream, milk, cinnamon, sugar, and salt. Heat until steaming. Slowly drizzle in the eggs, whisking continuously until mixture has started to thicken.