Meanwhile, fry the leeks and onions in low calorie cooking spray until they're nice, soft and golden. Once the cauliflower is cooked, drain and combine the two in a pot and mix, along with the vegetable stock pot. If you overcook the cauliflower, you'll find that it might go a little mushy. Don't worry, it'll still taste good!
(I sometimes find that mixing the vegetable stock pot in a little bit of boiling water in a mug until it's a thickish paste is better)