- 1.
Heat your oven to 200°C/Fan 180°C/Gas 6. Zest the lemon. Trim the courgettes and cut into thick batons. Spread out in a roasting tin and toss with the lemon zest and 1 tsp oil. Season well. Roast for 25 mins.
- 2.
Crumble the stock cube into a measuring jug. Pour in 750ml boiling water and stir till the stock cube dissolves. Set aside. Peel and finely chop the onions. Scrub and finely chop the potatoes.
- 3.
Tip the onions and potatoes into a large pan along with 3 tbsp water. Season. Sweat the veg over a medium heat for about 5 mins till the veg start to soften. Pour in the stock. Cover and bring to the boil. Simmer for 10 mins.
- 4.
Shred the lettuce leaves. Add them to the pan with the roasted courgettes and half the basil leaves. Simmer, uncovered, for 3 mins till the lettuce has wilted.
- 5.
Use a hand-held blender to blitz everything together to make a smooth soup (or leave it chunky, if you prefer). Squeeze in the juice from half the lemon. Taste and adjust the seasoning if you think it needs it.
- 6.
Peel and discard the skin from the flaky roast salmon. Flake the flesh into rough chunks.
- 7.
Spoon the soup into warmed bowls. Scatter the salmon flakes and the rest of the basil on top. Finish with an extra squeeze of lemon juice and some pepper.