Gently fry the onion and celery in half the olive oil for a few minutes until soft. Add the cauliflower and remaining olive oil and turn up the heat to medium-high so that after a 5 or so minutes the cauli is golden on some sides.
Add the cumin seeds, ginger and chilli, fry until aromatic.
Add pumpkin, potato and your other vegies and cook for another 2–3 mins, then add all the stock, cover and bring to a simmer.
Turn right down and simmer very low, covered, for 15–20 minutes.
Cool a little before blending with a stick blender.