Heat a few slices of butter and a little oil in a heavy skillet.
Brown the rouladen well on all sides.
Remove "browned" rouladen from pan.
Before the butter burns add cold water to deglaze.
Add meat back to simmering water.
Meat should be covered about 2/3 by water.
Cover with a lid and let the rouladen simmer for about 1 hour.
Remove meat and keep warm.
Beat together approximately 1/4 cup flour, 1 tablespoon of sour cream, & 1/2 cup cold water until smooth; stir into broth.
Bring to a boil, stirring constantly until thickened and bubbly.
Return meat to gravy and heat through.