Detach tops from parsley roots; tie together 6 large sprigs with kitchen string. Chop some of the remaining parsley leaves to make 1/2 cup (125 mL); set aside. Peel roots and cut into chunks.

In soup pot, melt butter over medium heat; fry onion, stirring occasionally, until soft, about 8 minutes. Add parsley roots, potato, salt and pepper; cook, stirring occasionally, for 4 minutes. Add stock and parsley tops; bring to boil. Cover and reduce heat; simmer until vegetables are very soft, 35 to 40 minutes.

Meanwhile, in small saucepan, heat oil over medium low heat; add chopped parsley and pinch of salt. Reduce heat to low and cook for 3 minutes. Transfer mixture to blender; blend until parsley is minced. Strain through fine sieve, discarding solids. Set aside.

Remove parsley tops from soup; purée soup. Stir in cream and bring to boil; ladle into bowls and sprinkle each bowl with scant teaspoonful (5 mL) parsley oil.

Makes 8 to 10 servings.

More Information

Tip: Parsley root is a type of parsley grown primarily for its long parsniplike roots. The herbaceous flavour is similar to parsnips but without the sweetness. Parsley roots are always sold with the tops, which can be used like regular flat-leaf parsley. Parsley roots can be cooked like carrots or parsnips and are delicious roasted with potatoes with meat or poultry. They are generally available in spring and autumn.