Heat the olive oil on medium heat in a large pot or Dutch oven.
Add the onions and garlic and sauté for 3-5 minutes.
Add the brandy and cook 2-3 minutes, until alcohol has mostly burned off.
Add the remaining ingredients and simmer for 20 minutes, or until sweet potatoes are soft throughout.
Remove from heat and let the mixture cool slightly. Remove the bay leaf.
Use an immersion blender or regular blender to blend the mixture until smooth.
Serve drizzled with crème fraiche and desired toppings (see post above for options)
Notes
If using a regular blender instead of an immersion blender, make sure to let the soup cool slightly as the heat will case expansion and could make quite the mess!
Double, triple, quadruple, etc. the recipe to make as many servings as you need - it is easy to adjust!.
Make this soup vegan by substituting vegetable stock for the chicken stock and eliminating the creme fraiche.
If you've got some extra pumpkins laying around, you can substitute pumpkin for the butternut squash.
You can roast the sweet potatoes beforehand if you want a slightly smoky, roasted flavor to the soup.