Slice the pork, grease with mustard, salt and pepper. Cut cucumbers into 4 parts and place between slices. Cut onion into rings and put in the same place. Tie the pork with cooking string, tightly clutching. Chop coarsely soup greens and place into the roaster. Place the meat on the top and bake for 30 minutes at 180 degrees Celsius. Pour 1 liter of water, add the broth cube and tomato paste, cook for 1,5 hours, pouting sauce some times.Thick the sauce with cream, salt and pepper.