Chop the walnuts. Wash and chop the herbs. Dab meat dry and tap flatter. Spread with sour cream and season with salt and pepper. Spread herbs and walnuts on top. Roll up meat into roulades and pin them with wooden skewers.
Heat the oil in a frying pan and fry the roulades for 4-6 minutes. Add red wine and bouillon and braise covered for 1-1 1/2 hours. Take the roulades out of the roaster, season the braising liquid with salt and pepper and thicken with sauce thickener.