- 1 1/2 pounds beef tenderloin, well trimmed, meat cut bite-sized pieces (about 1-inch square)
- 4 tablespoons butter
- 1/2 cup finely chopped shallots
- 2 1/2 cups sliced mushrooms
- 2 cups canned beef broth
- 3 teaspoons cornstarch
- 1 cup sour cream
- 2 teaspoons Dijon mustard
- Over medium high heat, gently cook beef tenderloin in 2 tablespoons of butter for about 2 minutes, until just seared on all sides. You will still be able to see red. Remove from pan and set aside in a rimmed dish or baking sheet so that you collect the juices.
- Return the pan to medium-high heat and cook the shallots and mushrooms in remaining butter until soft and wilted, about 5 minutes. Mix cornstarch into cold beef broth, whisk to blend. Pour into pan, and stir together with shallots and mushrooms until thickened, two or three minutes.
- Add sour cream and mustard, stir to blend. Add beef and juices from dish; stir over medium just till warmed through. Salt to taste.