Healthy, tasty and inexpensive, mackerel is one of my favourite fish. It's sublime if you can get it really fresh, but it is, of course, widely available smoked, and pairs brilliantly with acidic fruit such as rhubarb (technically it's a vegetable, but in the eyes of the US legal system, it's also considered a fruit), which is happily coming into season now. Try this quick compote for a speedy tasty lunch.