Trim the spring onions and separate the white and green parts of each stem. Finely slice the white ends (save the green bits for later in the recipe). Peel the garlic cloves and crush or finely chop them. Scrub the potato and finely dice it.

Pour 1 tbsp oil into a large pan and warm to a medium heat. Slide in the chopped white ends of the spring onions along with the garlic. Sprinkle in a generous pinch of salt and pepper. Fry for 2 mins, stirring, till slightly softened.

Add the chopped potato to the pan. Pour in 750ml boiling water and crumble in the stock cube. Return to the boil, then simmer for 15 mins, till the veg are tender.

Meanwhile, trim the ends off the cucumber and dice into small chunks. Trim the bases off the lettuces and shred the leaves.

Tip the cucumber and lettuces into the pan and stir well. Simmer for a further 2-3 mins stirring occasionally, till the leaves are wilted. Use a stick blender to whizz into a smooth soup. No stick blender? No problem. Transfer the soup to a blender (in batches if necessary) and blitz.

Finely slice the reserved green spring onion ends. Pour the soup into a couple of bowls and serve with the sliced spring onion greens, a drizzle of olive oil and a crack of pepper.