Chop onions and shallots. Heat a dutch oven or other heavy bottomed pan and add a couple tablespoons of canola oil. Add onion and shallots and sweat for 5 minutes or so. Add chopped garlic and stir for a minute. Add sausage and break it up so it doesn't clump together. Brown the sausage completely. Peel and roughly chop the yams and carrots. Add them and mix with the rest of the pot. Add stock and spices, mix and bring to boil. Once the pot comes to boil turn to simmer and simmer for 30-45 minutes or until the yams and carrots are tender. Fish out the cinnamon sticks and discard. Puree in batches using a food processor or blender until smooth. Return the blended soup to pot and taste, add salt and pepper if necessary.