1Combine the first 11 ingredients in a large Dutch oven. Add the roast; cover and marinate in the refrigerator 24 to 48 hours. Remove the roast from the marinade, reserving the marinade.
2Brown the roast in vegetable oil in a Dutch oven. Pour reserved marinade over roast; add crushed gingersnaps. Bring to a boil; cover, reduce heat, and simmer 2 to 3 hours or until the meat is tender, turning once.
3Place the flour in a heavy skillet; cook over medium heat, stirring constantly, 15 minutes or until the flour browns. Remove from heat. Gradually add water, stirring until smooth. Set aside.
4Remove the roast from the Dutch oven; set aside, and keep warm. Strain the pan juices and return to the Dutch oven; bring to a boil over medium heat. Stir in enough browned flour mixture to thicken the gravy. Slice the roast; serve with gravy.