Steak, Mushrooms & Onions

Mushrooms and Onions (S)
Steak (P)
Teaspoon Mustard 1/2 syn
I used frozen onions and pre chopped mushrooms. I put them in a saucepan together with a lid on, on a medium heat with a little fry light. The moisture from the frozen onions helped cook the mushrooms nicely. You could add a little fresh garlic or garlic powder to make garlic mushrooms if you fancied it.