This is another classic French dish, but it works very well in the US, since you can get very easily some very good quality trout. I bought some at whole foods, and it worked out beautifully. It is very simple to make, and will impress your guests for sure while delight them when they eat it :).
In some salted boiling water, throw the green beans, some pepper, and thyme. After 4-5 minutes, once the beans are cooked but still crunchy, remove from the heat and keep warm.
Ask your fishmongers to prepare the trout “butterfly” style. In other words, the fish becomes flat, one side with the skin and the other with the meat. Put some butter in a very hot pan, and once melt, put the fish, skin side down. Let it cook on that side until the very top is still pink but the inside seems cooked. Remove from the fish from the pan, throw more butter in it. Add some capers, lemon juice. Let it cooked for a minute, then add the beans and let it cooked for another minute.
To finish, put the fish on a plate, skin side down, and lay over it some beans, capers and the juice from the pan.