Preheat oven to 450 deg. Wash and dry game hens. Salt inside and out. Set vertical roasters in a roasting pan containing 1/4 inch water. Lower hens onto roasters. Truss wings to body of each bird. Paint each hen with plenty of mustard. Set pan on middle rack of oven and roast for 30 minutes. Remove from oven and allow to rest on frames.
If vertical roaster not available roast hens in roasting pan on a rack.