Party Steak Diane - cooking recipe

Ingredients

1 sirloin steak (2-inches thick and weighing about 5 lb.)
1 tsp. freshly ground pepper
1/2 c. (1 stick) butter
2 tsp. dry mustard
3/4 lb. fresh mushrooms, washed, trimmed and sliced
1 1/2 c. sliced green onions
1 Tbsp. lemon juice
1 Tbsp. Worcestershire sauce
1 tsp. salt (optional)
1/4 c. fresh chopped parsley

Preparation

I add a little dry vermouth.