I just made this yesterday. It is easy and yummy. Allrecipes.com gets the credit for the meat recipe. The gravy is my own.
Slow Cooker Roast Beef and Mushrooms:
Choose your favorite cut of beef. I used a rump roast.
Put 1 pound fresh mushrooms in bottom of crock pot
Place meat on top; Sprinkle with onion soup, pepper to taste
Add one can or bottle of beer.
Turn on high for 2 hours then reduce to low for 3 more (or) cook low for 6-7 hours. If the meat pulls apart easily it is ready.
Take out roast and allow to rest on a plate, cover with mushrooms. Pour remaining liquid into gravy boat if you desire au jus.
If you desire gravy: Transfer juice to frying pan and bring to a boil
In a separate container with a lid, add 3 TB flour, 1/2 cup milk, 2 TB sour cream (opt)
Secure lid on top and shake vigorously to combine ingredients; open and slowly add to frying pan.
Stir continuously until thickens into gravy.
Serve with potatoes, rice or noodles and a green vegetable.