Shindy,
Try putting the challa in the freezer and taking it out a few hours before Shabbos. At some point (preferable when the challa is pretty much defrosted) put it in the oven for about 20 minutes on a low setting or until it gets crisped. I find that it comes out any time as delicious as fresh challa (which I barely ever have because I am way to nervous to make Challa on Friday!)
You’ll get to do the mitzva of Hafrashas Challa as well as make more than one batch at a time. Try it. (you don’t have to tell your family it’s frozen; they will probably never know!)