Cucumber consists mostly of water, so it needs gentle and brief cooking to help it blend smoothly and bring out the flavours and to help prevent it separating once it's blended and chilled. Don't be tempted to add more lovage as it will really overpower the soup
1 small leek, roughly chopped and washed
1tbsp rapeseed or olive oil
2tsp plain flour
2 cucumbers, halved lengthways, seeds removed and disgarded and the flesh roughly chopped (reserve a quarter of one for garnish)
600ml vegetable stock
Salt and freshly ground black pepper
6-8 lovage leaves
For the garnish
150g haloumi, cut into 1cm cubes
1tbsp olive oil
Gently cook the leek in the olive oil, in a covered pan, for 2-3 minutes until soft. Add the flour, stir well, then gradually add the vegetable stock, bring to the boil and simmer gently for 15 minutes.
Add the cucumber and lovage leaves and remove from the heat. Blend in a liquidiser until very smooth. Strain through a medium-meshed sieve (a fine mesh will trap too many bits) into a bowl set over some iced water to cool it quickly and prevent discolouring.
Season to taste. Meanwhile, finely dice the rest of the reserved cucumber as small as you can and stir into the soup.
Heat the olive oil in a heavy, preferably non-stick, pan and cook the haloumi on high for 2-3 minutes, turning as it's cooking until it's crisp, then drain on some kitchen paper.
To serve, pour the soup into large chilled soup bowls and scatter the haloumi on top