In a large skillet set to medium high heat, add the oil and swirl the pan so it covers the bottom. Brown the roast on all sides. Transfer the roast to the slow cooker.
Sprinkle the salt, pepper and oregano over the roast. Spread over the horseradish.
Add the onion, mushrooms, Worcestershire sauce and beef broth.
Cover and cook on LOW for 9-10 hours without opening the lid during the cooking time.
If desired make gravy out of drippings, you can do that by following a recipe using flour and the drippings OR you can use the drippings in place of water in a gravy packet or two.
Enjoy!
Video
Notes
Nutrition Values are approximate and are not 100% accurate. Please use your own calculations if you require a special diet.