Add egg whites and beat 3 minutes. Add bread crumbs, stirring. Pour in cream a little at a time, beating between additions. The mixture should have the consistency of sticky roll dough. Refrigerate overnight. .
Place boudins in heavy saucepot and cover with equal parts milk and water.
Bring liquid to simmer and poach slowly for 25 minutes. Drain boudins, cool at room temperature, and refrigerate. Before final cooking, prick each boudin in three or four places with a needle to prevent bursting. Bush with melted butter and grill or dredge in flour and fry in butter at a slow temperature. Use within three or four days or freeze.