Heat the olive oil in a large saucepan over a medium heat
Add the leeks, basil stems only and celery with a pinch of salt and cook gently for 6–8 minutes until softened but not coloured
Stir in the garlic, broccoli & cannellini beans including their stock to the pan, pour over the stock so all the veg is just submerged
Bring up to a boil, then reduce to a simmer and cook for 6–8 minutes until the broccoli is just tender
Take the pan off the heat and add the baby spinach and basil, stirring them through the hot liquid so they wilt in the residual heat for 30–60 seconds
Blend the soup until completely smooth and silky, loosen with more stock if it's too thick
Stir through the smoked cheddar until it melts into the soup
Add the lemon zest, then taste and season generously with sea salt and black pepper
Ladle into bowls and serve with extra cheddar and a dollop of creme fraiche
