In a kettle of boiling salted water cook the beans for 5 minutes, or until they are crisp-tender, and drain them. While the beans are cooking, in a small saucepan melt the butter over low heat with the zest, the rosemary, and salt and pepper to taste and keep the mixture warm. Transfer the beans to a serving dish, add the butter mixture, and toss the mixture well. Serves 8. Gourmet November 1992