Soups - Creamy sweet potato and rosemary soup

Serves 4-6

3 T unsalted butter at room temp
3 T olive oil
3 large or 6 small shallots, thinly sliced
2-3 cloves garlic, minced
Kosher salt and freshly ground black pepper
2 6" long stems fresh rosemary
2 pounds (2-3) sweet potatoes, peeled, trimmed and cut into 1/2" pieces
6 cups low-sodium chicken broth
1/2 cup mascarpone cheese at room temp
3 T maple syrup

In 8 qt. stockpot, melt butter and oil over med-hi heat. Add shallots and garlic, season with s & p and cook for 3-4 mins until soft. Add potatoes, rosemary, and broth. Season with s & p. Bring mixture to a boil, reduce heat, and simmer until potatoes are very tender, about 20-25 mins. Turn off heat and remove rosemary stems. Using and immersion blender, blend the mixture until smooth and thick. Whisk in the mascarpone cheese and maple syrup until smooth. Season with s & p to taste. Keep soup warm over low heat until ready to serve.