Mix marinade ingredients together in large pan and place meat into the marinade, turning to coat both sides. Cover with plastic wrap and place in fridge for 4-12 hours. Can flip meat to other side once during marinade time if desired.
Slice onion and place in bottom of pot.
Heat oil in heavy skillet, and sear roast on both sides till well browned. Place roast on top of onion.
Sprinkle salt, pepper, thyme, rosemary, oregano, and cayenne on top of the roast. (I put fresh thyme and rosemary springs in around roast, sprinkled ground thyme, cayenne and oregano on top of roasts)
Dice garlic and place carefully on top of the meat. Arrange sliced butter over top of the garlic, and pour the balsamic vinegar, soy sauce, and broth into the crockpot.
Cover with lid and cook on 275° for 3 hours. 350° for 30 minutes, might need to add more liquid.
Remove from Dutch oven and cut against the grain several times. Shred with a fork and place back into the juice. Stir and serve over noodles or potatoes.
