Heat a generous glug of olive oil in a pot and sweat down the leeks, celery, garlic and rosemary
When softened, add the beans and the stock and gently simmer for around 20 mins
Add the juice of 1 lemon, lots of grated Parmesan, black pepper, a little salt and chilli flakes
Take the soup off the heat and blend until smooth
Taste to make any adjustments. Should be really herby, lemony, salty, creamy, a little spicy and delicious!!
Serve with a drizzle of extra virgin olive oil and the rosemary croutons
