- Combine marinade ingredients in large non-reactive saucepan. Bring to a boil. Remove from heat; cool slightly. Place beef roast and marinade in food-safe plastic bag; turn roast to coat. Close bag securely and marinate overnight or as long as 24 hours, turning occasionally.
- Preheat oven to 325°F. Remove beef roast from marinade; strain and reserve marinade. Pat roast dry with paper towel. Heat vegetable oil in a large stock pot on medium heat until hot. Place roast in stock pot; brown evenly. Remove roast from stock pot.
- Place roast, fat-side up, in large shallow roasting pan. Insert ovenproof meat thermometer so tip is centered in thickest part of beef, not resting in fat. Add reserved marinade; cover pan tightly with aluminum foil. Roast in 325°F oven 1-1/4 to 1-3/4 hours. Remove roast when meat thermometer registers 135°F for medium rare. Transfer roast to carving board, reserving liquid. Tent loosely with aluminum foil. Let stand 15 to 20 minutes. (Temperature will continue to rise about 10°F to reach 145°F for medium rare.)
- Meanwhile, in same stockpot, combine liquid from roast, 1/2 cup water, gingersnaps and sugar; bring to a boil, stirring occasionally until sugar and gingersnaps are dissolved. Whisk flour into remaining 1/2 cup cold water. Stir flour mixture into sauce; cook over medium to medium-high heat 6 to 8 minutes until thickened. Stir in browning and seasoning sauce and pepper. Keep warm.
- Carve roast into thin slices. Spoon sauce over beef. Serve with roasted potatoes and braised cabbage.