Crockpot Buttered Beef

Notes

Notes from Marshall: I've made this twice now. The first time I followed the recipe to the letter and found it decent but knew the recipe had potential with a little tweaking.
The second time, I did the following things to snaz it up: seasoned the beef with kosher salt, fresh cracked pepper, and garlic powder, browned the beef before adding it to the slow cooker, sauted 2 c. sliced mixed mushrooms and 1 onion sliced in the beef drippings before adding them to the slow cooker, 1/2 c. of red wine and added that also to the slow cooker, used 1/2 unsalted and 1/2 salted butter and then used low-salt soup mix to avoid all the saltiness.