In a large sauce pot, melt the butter over medium-low heat. Add the onion and garlic and cook until the onion is just beginning to brown, about 10 minutes. Stir in the squash, vegetable broth, 1 teaspoon salt and the Sugar Babies candies. Bring to a boil, cover and simmer until the squash is tender, about 15 minutes. Let cool slightly.
Using a food processor, and working in batches, puree the soup. Return the pureed soup to the pot, stir in the buttermilk and cook over low heat until heated through, about 5 minutes.