A glaze of Dijon-style mustard and orange marmalade is used to baste the Cornish game hens during roasting and to flavor the gravy.
Heat oven to 375 degrees F.
For glaze, whisk together marmalade, juice, mustard, salt and pepper in a small bowl.
Remove necks and livers from the cavities of the hens; reserve necks. Cut hens in half lengthwise. Cut out backs. Spread out the backs and necks in large roasting pan.
Reserve 1/4 cup glaze for gravy. Brush some of remaining glaze over hens. Place hen halves, cut side down, on top of chicken parts in pan.
Roast in 375 degree oven for 55 to 60 minutes or until instant-read thermometer registers 170 degrees F when inserted in thigh without touching bone. During roasting, brush top of hens with glaze every 15 minutes. Remove hens from pan to a platter; cover and keep warm.
Carefully pour off all but 1 tablespoon fat from roasting pan, leaving necks and backs in pan. Push hen parts to one side of pan; sprinkle flour over pan juices. Place pan over medium-high heat; cook 1 minute, scraping up any browned bits from bottom of pan. Stir in broth. Simmer 5 minutes to thicken. Discard backs and necks. Stir in reserved 1/4 cup glaze. Strain into sauceboat. Serve hens with the gravy.