Bring a large pot of lightly-salted water to a boil; drop in the green beans and return to a boil. Cook uncovered until the beans are bright green and barely tender, about 6 minutes. Drain and set aside.
Melt the butter in a large skillet over medium-low heat; whisk the cream, 2 tablespoons of Parmesan cheese, and nutmeg into the melted butter. Bring the mixture to a simmer. Gently stir the beans into the mixture to coat; season with salt and pepper. Return to a simmer, transfer to a serving dish, and sprinkle with 2 tablespoons of Parmesan cheese to serve.
