Pour the water, stock, peas and rice in the casserole and bring it to the boil. Let them simmer for 30-35min or until the peas and rice are tender. Remove any foam that forms on the top with a slotted spoon.
While the food is cooking you can prepare the added sides by washing and chopping them as desired.
Add salt, pepper and the lemon juice before using an immersion stick (or a heatproof blender) to blend it all together. You may otherwise leave the soup as is if you prefer the texture.
Serve warm with the additions as a side.
The soup thickens a lot when chilled but once reheated it thins out again.
I avoid using too much salt as we usually eat it with olives which can be quite salty as well