Add grape seed oil to frying pan and heat to hot. Add meat and brown on both sides. Remove meat and add celery and onions. Cook until onions are tender. Put the meat, onion, carrots and celery in a slow cooker. Stir remaining 2 tbsp. into pan drippings. Stir in can of tomatoes, beef bone broth and Worcestershire sauce stir in pan to blend and thicken. Pour over meat and vegetables in slow cooker. Cook on low for 8 hours or until meat and vegetables are tender. Remove meat and turn cooker to high to thicken sauce. Serve meat and and sauce over mashed potatoes.