Place beef rump roast, onions, vinegar, water, 1 tablespoon salt, 1 tablespoon black pepper, sugar, cloves, and bay leaves in a large pot. Cover and refrigerate for 2 to 3 days, turning meat daily. Remove meat from marinade and pat dry with paper towels, reserving marinade.

Season flour to taste with salt and black pepper in a large bowl. Sprinkle flour mixture over beef.

Heat vegetable oil in a large Dutch oven or pot over medium heat; cook beef until brown on all sides, about 10 minutes. Pour reserved marinade over beef, cover, and reduce heat to medium-low. Simmer until beef is tender, 3 1/2 to 4 hours. Remove beef to a platter and slice.

Strain solids from remaining liquid and continue cooking over medium heat. Add gingersnap cookies and simmer until gravy is thickened about 10 minutes. Serve gravy over sliced beef.

Prepare the Marinade:  Place all of the veggies and herbs in a heavy stock pot or Dutch oven along with the garlic, juniper berries, whole cloves, bay leaves, salt, sugar and peppercorns.  Add the red wine, red wine vinegar and water.

Bring the mixture to a boil, reduce the heat, cover and simmer for 10 minutes.  Turn off the heat and let the mixture cool down completely.

Or

Marinate the Meat:  Nestle the roast in the vegetable marinade and place the lid on the pot.

Let it marinate in the fridge for at least 4 days, preferably 7. (Traditionally, the marinating time is as long as 2 weeks!) Unless the meat is completely submerged under the liquid, turn the roast over once every day.

Remove the roast, pat it dry with paper towels, and strain the liquid from the vegetables. Reserve the liquid and the vegetables. 

Cook the Roast:  Rinse the pot out and heat a tablespoon or two of oil in it over high heat. Generously brown the roast on all sides.  Remove the roast and set aside.  If using bacon, cook the bacon until done. 

Leave about 2 tablespoons of oil/fat in the pot.  Place the strained vegetables in the pot (with the bacon if using) and cook for 5-7 minutes. Stir in the flour, cooking the mixture for a minute or two to eliminate the flour flavor. Add the liquid that you strained from the vegetable marinade, bring it to a boil, stirring constantly to prevent lumps.

Add the raisins, honey and crushed ginger snaps.  Return the roast to the pot.

Bring to a boil, reduce the heat to low, cover and simmer for about 2 hours (may need longer) or until the meat is very tender.

(Important Note: The longer you let the roast marinate the faster it will cook because the meat will be more tender from the start. So check on your roast periodically for doneness.)

When the roast is done, remove and transfer it to a plate, tent it to keep warm, and let it rest for 5 minutes before slicing.

Prepare the Gravy:  While the roast is resting, strain the gravy and return the gravy to the pot.  Taste and more sugar, salt and pepper as desired. If you want your gravy thicker, make a cornstarch slurry to thicken the gravy.  (Note:  The balance of sour to sweet is a matter of personal taste - adjust the flavor according to your preference. If the flavor is too strong for you, you can dilute it with a little water or broth.)

Spoon the gravy over the sliced Sauerbraten and serve immediately.

Serve with Homemade German Rotkohl and boiled potatoes, Homemade German Spätzle, Semmelknödel or Kartoffelklöße .  A few parts of Germany even serve it with Homemade Kartoffelpuffer.