Do ahead tips from smitten kitchen: When working with bread dough, you can refrigerate it or freeze it at almost any point in the process. When you’re ready to work with it again, you bring it back to room temperature and let it resume rising from where it left off. Give yourself a few hours: since the dough is cold, room temperature may take awhile to attain again. You can even assemble the whole thing, braided and filled, put it on the baking sheet, loosely cover it with plastic and either refrigerate it overnight or up to a day, or freeze it for up to a week (once frozen, wrap it more tightly in plastic before storing for long periods). When you’re ready to use it, take it out, bring it back to room temperature and let it complete its second rise before you brush and bake it.