In a large heavy based saucepan/dutch oven, melt the butter over low heat & fry the leek for 2-3 mins, or until soft.
25 g salted butter, 1 medium sized leek (white part only)
Once leek is soft, add garlic & stir for 30 secs, then stir through milk. Add cauliflower & potatoes then bring to a simmer.
1 kg cauliflower, 4 garlic cloves, 750 ml milk, 300 g potatoes
Simmer, partially covered for 15-18 mins, or until cauliflower & potatoes are tender. Remove from heat.
Using an immersion/stick blender, blend soup until smooth (see notes) and check for seasoning.
salt & pepper to taste
Divide soup between serving bowls, top with fresh parmesan, thyme and drizzle with olive oil if using, and serve with fresh parmesan on the side for each guest to add as they wish (see notes).
fresh thyme leaves to garnish, olive oil to garnish, 60 g fresh parmesan
Notes
Once you put the milk into the pot, you may find that it doesn't quite cover the cauliflower and potato. (At least I did!) As long as they are mostly covered, it should all still cook because we are going to partially cover the pot while it cooks. This stops the soup from cooking down too much, and also steams those small bits sticking out of the milk. Just give it a bit of a stir once or twice during cooking just to get them all mixed around.
Make sure you take the pan off the heat before you blend the soup. This helps it not splatter everywhere - still you need to be a bit careful when you blend it. Once it is blended you could add a bit more milk if you want a slightly thinner consistency, just put it back on the stove to heat through after you add it.
Parmesan - my recommendation is the more the better! My suggestion is garnishing the soup with parmesan to serve, and providing fresh parmesan on the table for diners to add more as they eat. I like the consistency of the soup as it is, but I want the flavour of the parmesan, and this way diners can choose their own amount.
*Please note that the amount of calories per serve is provided as a guide only, as ingredients and cooking methods can vary greatly*