Bring a saucean of salted water to the boil and blanch the beans for 4–5 minutes or until al dente, then refresh in a bowl of ice-cold water. Drain and pat dry with kitchen towel.
Heat the butter in a frying pan over a medium heat. Add the green beans and shallot and cook for 2–3 minutes until slightly al dente and well coated with butter. Season with salt and pepper and serve.