Courgette and spinach soup

I've been watching my courgettes and picking regularly but even so two managed to escape my eye and grew rather bigger than I wanted. 
So I made some courgette and spinach soup. I've been making this for a few years and the recipe is below. I started with this but now I tend to just add quantities of each depending on what I have. Most of my soups are made up as I go along, in my pressure cooker. I like to make batches of this to freeze as it is a good way of storing courgettes for winter. 
I made this batch with New Zealand Spinach. (Seeds available from Simpsons Seeds),

 It is a much more fleshy leaf than the annual or perpetual spinach and has quite a strong flavour.

New Zealand Spinach makes a low sprawling plant which does seed from year to year. It takes up more space than you expect. It is quite prolific now in September.
Courgettes are definitely slowing down now but this is good for the glut in summer and is delicious. 
I finally found the recipe after looking through all my books. It is in a very old Cranks book. 

1 onion
1 large courgette
1 medium potato
4oz spinach
oil
parsley
2pt stock
1/4pt double cream
seasoning
Saute onion and courgette until onion is transparent. Add potato, spinach, parsley and stock. Bring to the boil and simmer for 20 min. 
When cool, blend in small quantities.
Return to saucepan and and stir in cream and add seasoning to taste. 

Looking at this recipe I realise I have distilled it down to it's simplest. Usually I only use onion, spinach, courgette and stock. I'd forgotten the recipe has parsley and I don't usually have cream. Anyway it tastes good!