Cut tips from the asparagus (about 3cm from top) and reserve for garnish. Chop the remaining asparagus stalks up into 3cm pieces and set aside.
Place large saucepan over medium heat, add the olive oil, butter, onion, leeks and garlic and sauté for about five minutes, stirring often, until onion is limp and translucent
Add the asparagus pieces and the thyme and sauté for another 5 minutes.
Pour in the hot stock and bring to the boil, reduce heat and simmer, with the lid on, for about 15 minutes until the asparagus pieces are tender. Take off the heat, cool slightly.
While the soup is cooling bring about 500ml water to a rolling ball in a small saucepan with a good pinch of salt.
Add the reserved asparagus tips and boil for about 3 minutes just until done. Refresh immediately in some icy cold water to stop the cooking process. Set aside until needed.
Add the chopped parsley, zest and juice of the lemon to the slightly cooled soup and blend until smooth with a stick blender or food processor.
Return to the saucepan, add the cream or crème fraiche (if using) and the parmesan cheese. Season to taste and stir over heat just until heated through.
Serve with a drizzle of extra virgin olive oil, a few asparagus tips and some extra parmesan cheese.
Reprinted with permission of Kitchen Diary. To see more
recipes, click here.