Melt butter in a large saucepan and add the garlic, onion and rosemary. é over medium heat until onions are translucent. Deglaze the pan with wine and scrape the bottom of the pan. Add stock and bring to a boil, reduce the heat and simmer for 5 to 10 minutes until the beans are tender. Remove the rosemary sprig and puree the soup to a smooth consistency. Season to taste with salt and pepper. This soup may be served cold and can be chilled* at this point. Or, keep warm, if desired.