Preheat the oven to 180ºC (fan) / 350ºF / Gas Mark 4.
Trim the ends off the courgettes and slice them into chunks about 1cm thick. Place on a baking tray / roasting tin.
Trim the ends off the leek and slice into rounds of a similar size. Place on the baking tray along with the garlic cloves (still in their skin), then drizzle everything in the olive or rapeseed oil, season with salt and black pepper, and toss everything together until fully coated in the oil.
Roast the veg for 40-45 minutes, turning occasionally, until soft and golden brown (but not too charred).
Meanwhile, make up the vegetable stock with boiling water in a heatproof jug, then tip in the frozen peas and set aside to let them thaw.
When cool enough to handle, squeeze the flesh out of the roasted garlic cloves and discard the skins.
Tip the roasted vegetables into a saucepan, along with the stock and peas, and bring to the boil. Simmer for 2-3 minutes until the peas are just cooked through.
Add most of the dairy-free parmesan and basil (keep a little of both back for garnish), and the dairy-free cream. Use a hand blender to blitz to a smooth purée (or tip into a blender or food processor) then taste and add salt and black pepper as required.
To make the croutons, cut the ciabatta into cubes, toss in the olive oil and bake in the oven for 5 minutes until crispy. Add the pine nuts and cook for a further minute until just starting to brown.
Serve the soup with a sprinkle of basil and dairy-free parmesan, topped with the croutons and pine nuts, and with a swirl of dairy-free cream.
Video
Notes
Don't skimp on the blending time A decent blender will make this soup silky smooth - do keep the blender (or food processor) running for a good minute or so for the smoothest possible soup. It is tempting to just blitz for 5-10 seconds until it looks puréed, but in fact it takes longer than you think to get a really super-smooth result, and to blitz through those courgette skins and leeks. Take your time!Keep an eye on the roasting vegetables How long the courgettes take to roast will depend on their size, water content, and how thickly you have sliced them. They could take anything from 30 minutes to an hour so keep watching and turn them occasionally. You want them to be golden brown but not charred or shrivelled.