Clean, wash and pat the radishes dry, then cut into fine slices. Rinse the chives, pat dry and divide into rolls. Cut the cress from the bed.
Mix the vinegar with salt and pepper, stir in the mustard and broth, then whip in the oil. Peel the onion, dice finely, stir into the marinade.
Cut the sausages into slices and fry them in a little fat over a low heat. Take out and pour off the frying fat. Deglaze the roast with the marinade, remove the pan from the heat.
Return the sausages and fold in the radishes. Mix the salad with the chives and cress and serve lukewarm.