In a large bowl, mix the sherry, dill, horseradish salt, pepper, Spank It Kopita Grecian blend or substitute spices, paprika, bay leaf, garlic powder and mix. Place the meat in the bowl and marinate for at least an hour but overnight is good too.
In a large, frying pan, heat the olive oil and saute onion and garlic with a pinch of salt and pepper on medium high heat for about two minutes until onion becomes translucent. Transfer everything (including onion and garlic) to crockpot.
Pour the marinade over the beef. Add 3 tbsp of red wine vinegar and beef broth. Cover tightly and put heat to medium low (6 hours).
Remove meat carefully and place on a plate. Cover with tinfoil and let rest for 10 minutes.
Meanwhile, add butter and two tbsp of flour to the braising liquid and stir thoroughly. Cover and simmer for another five to ten minutes until thick and smooth, stirring occasionally. This will be used as a gravy.
Slice meat against the grain and drizzle gravy on top. Serve it bit@h.