Select the VEGETABLE function and heat the butter in the Russell Hobbs DualChef pot, add the leeks and celery, and cover with pressure cooker lid to sweat over for 5 minutes.
Remove the lid, add the stock, lemon zest and lemon juice and bring to a boil.
Select keep warm function and simmer for 10 minutes.
Remove from the heat and allow to cool. Add the basil, blend in a blender until smooth.
Chill for an hour.
Serve chilled, with a swirl of a 10ml cream and garnished with basil leaves.
