Creamy Curried Sweet Potato Soup

1 ½ tablespoons olive oil
1 2/3 cups coarsely chopped onion
1 large clove garlic, coarsely chopped
1 tablespoon coarsely grated ginger
1 teaspoon ground cumin
½ teaspoon ground coriander
1/4 teaspoon ground cardamom
1/4 teaspoon turmeric
1/8 teaspoon hot pepper flakes, optional
2 ½ pounds sweet potatoes, peeled and sliced 1/4 inch thick
6 cups no-salt-added chicken stock
Salt and freshly ground black pepper to taste
Fresh goat cheese

1. Heat oil in a nonstick pot large enough to hold all the ingredients. Sauté onion until it begins to brown (about 10 minutes). Add garlic and sauté, stirring, for 30 seconds.

2. To make the curry flavoring, add ginger, cumin, coriander, cardamom, turmeric and optional hot pepper flakes and stir well. Add sweet potatoes and stock and bring to a boil. Reduce heat and simmer for about 20 minutes until potatoes are soft.

3. Remove the sweet potatoes from the soup and mash; return to pot (if you don't mind washing more stuff, you can puree the soup in a blender or food processor). stir well, season to taste with salt and pepper. Serve hot in mugs with a spoon of cheese on top and stir a bit to melt the cheese.