Start by chopping the celery, carrot, onion and garlic. The recipe says to chop them finely but it'll be pureed later so it's up to you how finely you want to chop.
Saute the vegetables in the oil until softened.
Next add the cumin, chilli flakes, salt & pepper and the chopped butternut squash.
After 5-10 minutes of sauteing the squash should be soft so add the stock and lentils.
Simmer the soup until the lentils are soft and swollen with the liquid. Allow to cool for a few minutes and then puree with an immersion blender or food processor.
Sprinkle chopped parsley and paprika over the served soup along with a squeeze of lemon.