Fortunately the two little plants that managed to battle the elements (and the neighbours heavy pawed cat) were rather heavily laden and so I had enough to make a meal. They are such a dark colour and look so lovely in the garden it was a shame to pick them. The plant is also a fantastic purpley green.
I topped and tailed the beans and steamed them gently. I was hoping this would retain some of their purple colour but, unfortunately, they went entirely green! I find that beans are extremely happy with a little lemon juice. I melted a little butter and fried some chopped shallot then squeezed in a little lemon juice to sharpen it up.