Preheat oven to 375f
Grease 2 12-inch loaf pans
Divide dough into four pieces.
Roll each piece to a 10x7 rectangle and spread 1/4 of the filling and 1/4 of the chocolate chips on it.
Roll into a log.
Repeat with the next dough piece, and then twist two logs together and tuck ends under.
Place a twist (two logs) into each loaf pan.
Brush with yolk and a little water.
Bake 45 minutes or until very brown on top.
Cool for 20 minutes in the pan. Don't try to eat it right away or you'll burn your tongue on boiling butter or margarine!