1 1/2 lbs whole celeriac
3 Tbl butter
4-5 cups chicken broth (or vegetable broth)
light cream (optional)
salt & freshly ground pepper
Wash leeks and slice enough of the white and light green parts to make 2 cups. Peel and chop celeriac into 1/2 inch cubes, enough to make 3-4 cups; place in acidulated (lemon) water. Peel and coarsely chop potato; add to celeriac in water.
Melt butter in soup pot, stir in leeks, and cook until wilted. Drain celeriac and potatoes; stir into leeks. Add 4 cups of broth. Bring to boil, reduce heat, cover, and simmer until vegetabes are tender, 20-25 minutes. Pass through a sieve or puree in food processor or blender. If very thick, thin with optional light cream and additional broth. Season with salt and pepper to tast. Makes 8 cups.
Source: From Asparagus to Zuccini