· 2 pounds beef chuck, trimmed of excess fat and cut into thin slices (I used stew meat
· 1 large onion, thinly sliced (I used mandolin)
· 1 pound white mushrooms, trimmed and halved (or quartered, if large)
· Coarse salt and ground pepper
· 1 cup beef broth
· ¼ to ½ cup of sherry (optional)
· 3 tablespoons cornstarch
· 1/2 to 1 cup sour cream
· 2 tablespoons Dijon mustard
In a 5- to 6-quart slow cooker, toss beef, onion, and mushrooms with 1 1/2 teaspoons coarse salt and teaspoon pepper. Pour over broth and sherry over all. Cover, and cook on high until meat is tender, about 6 hours.
In a bowl whisk cornstarch with 3 tablespoons water. Ladle 1 ½ cups cooking liquid into measuring cup; whisk to combine. Pour into a small saucepan, and bring to a boil; cook until thickened, about 1 minute.
With slow cooker turned off, stir in cornstarch mixture – mix well. Then sour cream and mustard.
Serve beef over noodles.