Brush the roast beef with mustard and season with salt, pepper and paprika powder.
Cut off a sufficiently large piece of roasting tube, tie it at one side and place the meat in it. Eight the onion, halve the stock cube and place it on the left and right of the meat. Pour in the water and close the roasting tube tightly on the second side as well. Pierce the tube at the top 10-15 times with a pin.
Cook in the oven preheated to 200 ° C top / bottom heat for approx. 100 minutes.
Carefully cut open the roasting tube, remove the meat and put the sauce in a saucepan. Puree the onions, add Cremefine and a dash of red wine to the sauce, bring to the boil briefly and bind as desired with a dark sauce thickener.