This is an adapted version of Julia Child’s Watercress soup from ‘Mastering the Art of French Cooking’. I used yogurt instead of cream, added lemon, which did a lot for the flavour at the end, and I did not use flour to thicken it.
This served five people
250g watercress – tender stems and leaves, washed
1 large onion, finely chopped
1 ½ litres chicken stock (heated until hot)
2 egg yolks
2 tablespoons Greek yogurt or crème fraiche
How I made it:
Soften the onions in butter in a heavy bottomed pan on a medium/low heat with the lid on, and cook until they’re translucent (5-10 minutes). Then add watercress and allow it to wilt. Add the stock. Take off the heat and blitz the soup (optional is also to sieve it if you want to be really old-school French – they love to sieve everything). In a large heatproof bowl e.g. pyrex, beat together the egg yolks and the yogurt/crème fraiche. Gradually ladle some of the soup into the egg/yogurt mixture until your bowl is full. Return it to the soup and cook on a low heat (NOT so high the soup simmers) for a few minutes. Season well with salt, and a touch of pepper. Serve into warmed bowls and squeeze lemon juice over each bowl.
A glass of prosecco.