Heat vodka or vinegar to boiling in dutch oven. Scald meat on all sides. Remove meat and discard the vodka.
Season flour with salt and pepper. Dredge on meat. Melt the butter in dutch oven and sear the beef on all sides. Add the onion, beef stock, and demi glace. Bring to a boil and reduce heat to low and simmer 3 hours. Adding more beef stock if necessary.
Meanwhile mix all ingredients for stuffing together. When meat is tender remove to a cutting board. Heat oven to 375 degrees. slice the meat to create pockets for stuffing.
Stuff each pockets with stuffing. Add roast back to pan and place in oven for 20 minutes. Serve with gravy drizzled over.