Peel the celeriac and chop into small shanks. Set a few very small pieces aside for garnish.
Put the bigger pieces in a pot with the finely chopped leeks and spring onions. Cover just with water. Add a colander or sieve over this but not letting it touch the water.
Now drop the smaller celeriac pieces into 1/4 of the lemon juice and rub it into the celeriac. Remove and put into the sieve over the other vegetables in the water bring to boil thus cooking the leeks , bigger chunky celeriac and spring onions and steaming the smaller celeriac pieces at the same time.
When the smaller pieces are almost cooked remove and set aside in another 1/4 of lemon juice.
Add all other ingredients except the 1 extra tablespoon of lemon juice and the cheese to vegetables in the pot.
Simmer for five minutes
Puree the soup, add more water to reach consistency you prefer ,add the cheese and ensure it I melted
Gently fry the smaller pieces of celeriac until they just caramelise do not fry brown or they go bitter
Finally season to taste with rest of lemon juice, cayenne pepper and salt if needed and arrange the smaller pieces of celeriac sprinkled with some of the green from the spring onions.
