Heat the oil in a large saucepan,
add the leeks and celery, and cook for
8 mins until soft. Add the courgettes
and garlic. Cook gently for 5 mins more.
Pour in the stock and simmer,
covered, for 10 mins. Add the
asparagus, peas and broad beans,
and cook for a further 4 mins, until just
cooked through. Stir in the chopped
basil and season well. Scatter with basil
leaves and serve with crusty bread.