Wipe tenderloins with damp cloth; split open.
Lay flat; rub with 2 tablespoons melted butter.
Combine bread crumbs, 1/3 cup boiling water, egg, onion, parsley, salt, celery salt, sage, pepper and remaining butter.
Beat until light; spread on tenderloin.
Roll up tenderloin; tie with string.
Arrange in baking pan; sprinkle with salt lightly.
Pour 2/3 cup boiling water in pan.
Bake at 400 degrees for 1 hour or until tenderloins are tender.
Cut and remove strings.
Gravy may be made from drippings in pan, if desired.