Season the beef with salt and smoked paprika. Add the olive oil to a cast iron or stainless pan over high heat. Add the beef and sear on all sides. Remove from heat and then add optional steak seasoning. I do this after it's removed from the heat so it doesn't burn and stick to the pan.
Transfer the beef to the crockpot, and return the pan to the high heat. Add the butter to the pan and when it melts, add the onion and mushrooms. Cook for five minutes, moving around consistently to caramelize the onions.
Add the minced garlic, and move it around in the pan for about a minute. Then, add the remaining ingredients, (except the parsley) and stir till well combined. Allow the mushroom and onion gravy to come to a slow boil.
ransfer the gravy into the crockpot and stir it in with the beef. Set the crockpot to low for six hours, or high for four hours.
Check meat for tenderness, add fresh parsley and serve with your favorite side.