brioche dough

This dough has a lot of butter and a lot of egg in it.  It's also salted.  Theoretically, according to Harold McGee, all that should interfere with rising.  This dough will not be ready for three days.  Presently it's fermenting in cold storage. 

The sponge was brought about rather carelessly. A small amount, about two ounces,  sourdough starter was revitalized.  This took awhile, it had languished and was nearly dead.  Once reactivated, it was used to inoculate about half this volume.  Then that amount was doubled, not with water and flour, but rather with egg and butter and flour.  That's what makes it brioche.  The final amount was determined by the capacity of my mixer which is large and heavy-duty.  

So this will be a sourdough brioche.  Hey!  It's what the lady wanted.