Heat oil in large saucepan over med heat. Cook leek for 2-3 mins until soft. Add barley and cook, stirring, for 2-3 mins until lightly toasted.

Heat stock and water in a saucepan over med heat until boiling. Add to barley mixture, one ladelful at a time, stirring until absorbed. Continue adding stock for 40 mins until all stock is absorbed and barley is tender.

Add zucchini, asparagus, green beans, parmesan and butter and mix well. Cover and set aside for 5 mins until creamy. Serve with extra parmesan.