While it's tempting to just throw the raw beans directly into the skillet with the garlic butter, I recommend you blanch them first. Blanching the beans will give you crisp, snappy, evenly cooked beans that need only a brief turn in the skillet to warm through and get coated in the garlicky butter. If you try to cook them raw in the skillet, you could end up with burned garlic and unevenly cooked beans.