Beef in Peppercorn Sauce

Ingredients

• 450 gram (1 pound) frying steak, cut into strips

• 2 tablespoons soured cream

• 100 gram (4 ounce) button mushrooms, halved

• 2 teaspoon cornflour

• 150 millilitre (¼ pint) beef stock

• 1 tablespoons Black Peppercorns Mill

• 1 teaspoon wholegrain mustard

• 1 tablespoons oil

• Sea Salt