Created by RecipeReader on October 28, 2013
Step 1: In an 8-quart stockpot, melt the butter and oil together over medium-high heat.
Step 2: Add the shallots and garlic, season with salt and pepper, and cook until soft, about 3 to 4 minutes.
Step 3: Add the sweet potatoes, rosemary and chicken broth. Season with salt and pepper, and bring the mixture to a boil. Reduce the heat and simmer until the sweet potatoes are very tender, about 20 to 25 minutes.
Step 4: Turn off the heat and remove the rosemary stems.
Step 5: Add the mascarpone cheese and maple syrup.
Step 6: Using an immersion blender, blend the mixture until smooth. Season with salt and pepper, to taste. Keep the soup warm over low heat until ready to serve.
Step 7: Cook's Note: The soup can also be pureed by ladling, in batches, into a food processor or blender and blended until smooth.