In America, these tiny fresh string beans are reserved for special occasions simply because they are so much more expensive than the ordinary variety. When they are served to me, it always makes me feel like an esteemed guest.
Place a steamer insert in a large saucepan with a lid, and add water to come just under the steamer. Bring the water to a boil.
Add the haricots, placing them so that they lie next to each other. Cover and steam the haricots over low heat until just tender, 6 to 8 minutes.
Place the haricots on the dinner plates and place a teaspoon of the butter on top of each serving. Sprinkle