Thai Curry Sweet Potato Soup

The weather outside has been frightful! All winter we waited for rain and none came and then as soon as I was taking out the sandals and getting ready for spring a seemingly endless winter storm hit. Hail, sleet, allegedly some snow, thunder and lightening the likes I have never seen in the 10 years I have lived in this country and lots of wind and rain. Well, since winter decided to return to us so abruptly I had to go back to making winter food and make soup. I thought of this soup because it required all the ingredients I had lying around and I wanted something a little more exotic than the usual. I haven't had that much Thai food in my life but what I have had I have loved. I love the curry, coconut, chili and cilantro combo and I love the combination of sweet, salty, sour and spicy that defines a lot of Thai food. This soup is easy, exotic and super duper delicious. Really. I 'm not just saying that. I promise. This soup has an interesting ingredient in it that at first seems absolutely bizarre but that is crucial to the taste and depth of flavor- peanut butter. Thai food uses a lot of peanuts and peanut butter and though many often associate peanut butter with sweets it is deliciously savory in this soup and helps to cut a little of the sweetness of the sweet potato and coconut. Did  I mention that it's really really good? I don't often go on and on about soups which is usually my least favorite course but this one is a winner. Enjoy!

2 Tablespoons canola or olive oil
1 medium onion
1 tsp fresh grated ginger
3 cloves garlic, minced
3 Tablespoons Thai red curry paste (in a pinch you can use Thai Red Curry Sauce instead)
2 medium sweet potatoes, peeled and chunked
4 cups chicken or vegetable stock
1 can (400ml/14oz) coconut milk
1/4 cup chopped cilantro
1/4 cup natural peanut butter
1 Tablespoon lemon juice
1 Tablespoon Sriracha sauce, optional
salt and pepper to taste

Heat the oil in a pot and saute the onion, ginger and garlic together until the onion starts to become translucent. Add the curry paste and saute until just fragrant. Add the vegetable stock and bring to a boil. Add the sweet potatoes and let it cook on medium heat until the sweet potatoes are soft, about 15 minutes. Add the coconut milk, cilantro, peanut butter, lemon juice and sriracha and season with salt and pepper. Cook another 20 minutes over medium heat until all the flavors have blended together. Blend with an immersion blender and serve.