In large non-metal bowl, combine red wine vinegar, red wine, onions, carrots, bay leaf, whole allspice, whole cloves, peppercorns and salt.
Place roast in marinade, cover and refrigerate 3 days, turning once daily.
Remove roast from marinade; wipe dry. In a large saucepan, heat the marinade over medium-low heat. Melt 1/4 cup butter with the oil in a Dutch oven over medium heat. Brown the beef on all sides, sprinkling the flour over it as you turn it.
Pour heated marinade into Dutch oven with the roast, cover, reduce heat to low and simmer 3 hours, until beef is tender.
Pour the marinade off from the meat, skim off the fat, and strain. In a large skillet over low heat, melt remaining 1/4 cup butter with sugar. Cook and stir until golden in color.
Pour in the strained marinade slowly, stirring until smooth and thickened.
Sprinkle in the gingersnaps.
Pour sauce over the meat in the Dutch oven, return the pot to low heat and simmer 30 minutes.
