- With the rack in the middle position, preheat the oven to 150 °C (300 °F).
- In a large ovenproof pan, brown the meat in the oil. Season with salt and pepper. Set aside on a plate.
- In the same pan, brown the onions and mushrooms. Add oil, if needed. Add the garlic, mustard and cook gently for about 1 minute. Return the meat to the pan and add the broth and sauce. Bring to a boil. Cover and bake for about 2 hours and 30 minutes. Remove the cover and continue cooking for about 30 minutes or until the meat is fork tender. Add the parsley and adjust the seasoning.
- Serve the meat into chunks with new potatoes and sour cream.