Sweet potato, chilli & coriander soup

The weekend is a time in our house when wonderful smells abound.  It's when we both have time to cook because we're at home, and it's when we try new things or whip up something for during the week.

One of our goals this year is to take lunch to work more often rather than buying it.  Home made food tastes better, costs less, and you know what you're getting!  Today I've made a batch of sweet potato, chilli & coriander soup, which I'll decant into soup bags for the freezer.  We can then grab a bag out and take it for lunch, along with a home-made roll or two.

This is a recipe that I've been making for a while.  Sweet potato is known as kumara in New Zealand, and it tends to come in two varieties: the orange skinned, orange fleshed variety; and the red skinned, yellow fleshed variety.  For this soup, you want the orange-skinned version - it makes a wonderful creamy soup.  The red skinned ones make amazing chips.

Ingredients
100g fresh coriander, roots attached if possible
1 Tbsp vegetable oil
1 large onion, coarsely chopped
2 cloves garlic, crushed
1 Tbsp sambal oelek (less if you like it less spicy)
1.2kg sweet potato, peeled and chopped into chunks
1 litre water
500 ml vegetable stock (gluten free)
160ml coconut milk

Don't worry too much if you can't get coriander with roots - I find it's hard to track down over here.  If you do want to use the roots, then try your local Middle Eastern grocers, as that seems to be the best place to get it.

Sambal Oelek is an Indonesian preserved chilli that you'll find in jars in either a speciality supermarket or perhaps in the international aisle at your local supermarket.  It keeps for a long time in the fridge once opened.

Method
Wash the coriander roots carefully to remove all traces of dirt, sand and soil.  Finely chop enough of the root, or stems if you don't have roots, to make 2 tsp.

Heat the oil in a large saucepan.  Add the coriander root, onion, garlic and sambal oelek.  Cook over a low heat until the onion is soft and translucent.  You don't want to brown the onion, just cook it through to soften it. This will take about 10 minutes.

Add the sweet potato, water and stock and bring to the boil.  Leave to simmer, uncovered, until the sweet potato is soft, around 15-20 minutes.

Remove from the heat and blend to a smooth consistency.  Add the coconut milk and stir through well.

Serve sprinkled with freshly chopped coriander leaves.