This is a work in progress but the recipe so far goes like this:
1 celeriac, peeled and diced with the bobbly bits taken off
1 small onion
2-3 cloves crushed garlic
Garam masala (half a teaspoon)
Cumin (1 teaspoon)
salt and black pepper to season
enough chicken or vegetable stock to cover
Cayenne pepper to finish, if you like that sort of thing
Peel and chop the celeriac, onion and potatoes and halve and slice the leeks.
Start with the onion as ever, softening it for a few minutes before adding the garlic to cook down. Then add the rest of the veg, cover and sweat gently for a few minutes. Add in the stock and spices, cover and leave on a low heat until the vegetables are tender.
Using a hand blender (and in my case, goggles and a full waterproof boiler suit - you know the drill, be careful and sit the pot on a folded tea towel so it doesn't go gallivanting around the work surface), blend carefully until smooth.
Check the thickness level - if it needs extra stock, add now and mix well over a low heat. Check for seasoning at this point too.
When you're ready, serve it up with a dust of cayenne pepper on top and some nice bread if you're really starving.