Budget friendly, nutritionally dense and very tasty. This is a perfect cold day soup to warm your bones. Alternatively, this soup can be eaten chilled on a warm day! You can make the broth from scratch or just use filtered water to save a little.
Add the butter and leeks to a medium sized pot, pre-heated on medium heat. Sweat (sauté without browning) the leeks for a few minutes, stirring occasionally.
Add the garlic, oregano salt, pepper and coriander to the pot and sauté for another 2 minutes.
Now add the yams, potatoes and vegetable broth or water. Bring to a boil and then reduce heat to medium low. Simmer until the yams and potatoes are cooked and soft then remove the pot from the heat and let it cool for 5 minutes.
Add to a blender or food processor and puree until smooth. Alternatively you can use an immersion blender.
Return the soup to a pot and re-heat if serving immediately, or transfer to storage containers and refrigerate or freeze.
Chicken broth is also another option for this soup.
You could skip the yams and double up the potatoes and/or omit the fresh oregano to bring you even more savings.