This is one of Orla Broderick’s 100 Great Soups.

1 tbsp olive oil
1 leek (or onion)
bunch fresh watercress, carefully washed
2 apples
1/2 lemon (juiced)
2 potatoes
1 pint chicken or veg stock
1 tbsp greek yoghurt (optional).

Finely chop leek and watercress stalks (I just cut off the top 1/3 and put aside).  Peel and cube the potatoes.  Cube the apples.  Fry the leek, potatoes and stalks in the oil for a few minutes, then add the apples, stock and lemon juice.  Simmer for 15 mins.

Chop the watercress leaves finely and add to the pan.  You can save a handful for garnishing if you wish.  Simmer for a further 10 mins.  Blend and season.  Stir in the yoghurt and check for seasoning again.  Serve with some crusty bread.

The sweetness of the apple works very well against the peppery watercress and the lemon.  A lovely starter or light lunch.