Hemp Cream of Celery Soup (Thermomix)

The following is adapted from the Cream of Celery Soup at the thermomix forums. I've changed it so it's dairy free and uses less coconut milk drink in making the roux. I've partially done this by adding hemp seeds to the soup mix before blitzing to give creaminess and omega 3's and protein. Pumpkin or sunflower seeds would also work and are cheaper than hemp seeds, although I find they need soaking beforehand or they taste a bit strong. You can follow the original recipe using either real, soy or coconut milk drink if you prefer, this is just a little thriftier if you need to use specialist non dairy, non soy milk.

Ingredients
1 bunch celery, chopped
1 onion, quartered
1 small carrot, chopped
1 small potato, chopped
1 teaspoon salt
boiled water up to thermomix half mark.
100ml shelled hemp seeds (add later)

For the Roux
1 heaped tablespoon dairy free spread
2 tablespoons gluten free flour
100ml Kara Dairy Free Coconut Milk drink (or soy, almond or other high protein non dairy milk. Rice milk won't work for this)

Making the soup:
Put the soup ingredients, minus the hemp seeds, into the thermomix bowl, and cook on 100C for 20 minutes on speed spoon.

In the meantime, make the roux as follows:  Melt the butter in a pot on the hob on medium heat (you don't want the spread to fry, just melt), when that's done, add the flour and stir gently with a whisk. Add the coconut milk and keep whisking. Turn the heat up to medium high and keep whisking until a thick sauce develops (the roux should coat the back of a spoon) then switch off the heat and move the pan off the heat source.

When the soup is done cooking in the thermomix, add the hemp seeds, then cover the lid with a tea towel (to prevent any splashes) and slowly move the dial up from 1 to 9 for 1 minute. The thermomix will shake about a lot and the tea towel will feel hot, so maybe use two. carefully remove the lid, then add the roux mixture to the soup, cover again and mix on speed 3 for 10 seconds.
Season to taste, and enjoy! This is a very creamy, comforting soup and you'd never know it was dairy free.