It's such a simple recipe - microwaved and much from the store cupboard - that I'm almost embarrassed to give it but it was so good I'm going to. No accurate measurements either, I'm afraid, but here goes.
Put 1 large head of cauliflower, divided into segments, vegetable stock - I used 2 good quality cubes in about a litre of water - and about a handful of dried onion flakes into a microwavable container and cook until the cauliflower is tender. It took about fifteen minutes on high in my microwave. Of course, you could cook it on the stove and I sometimes do but this was what I did last night.
When the cauliflower is cooked, add a large handful of parsley leaves, stalks removed. If you don't you end up with gritty little bits of stalk. Ask me how I know. Add three or four heaped tablespoons of full cream powdered milk and blend together with a stick mixer or in a blender. It'll be fairly thick and you might need to add a little boiling water. I try not to add too much, partly because we like it to be substantial but also I don't want to water down the flavour. Grate some cheese into the hot soup, say 50-60 grams but not too much, because you don't want to overpower the flavour of the other ingredients, and serve.
That gave us about 5 serves as a main meal dish and it was filling and delicious.
Note: I discovered using powdered milk this way one day when I was making a more traditional cauliflower soup and ran out of milk and it worked so well I've used it ever since to make this soup.