If you are using fresh haricot vert, cook in a pot of boiling water for 2-3 minutes; shock in ice-cold water with 1/2 tsp white vinegar added, drain and set aside. If using frozen, thaw and drain.

In a large saute pan over medium heat, melt the butter until bubbling but not browned. Add the shallot and garlic, and saute until softened, about 30 seconds. Add the beans and toss a couple of times. Add the salt and pepper and continue to saute until all is hot throughout, approximately 2 minutes. Serve immediately.