Peel, trim and roughly chop all the vegetables and trim the herbs. Put into a food processor and blend, pulsing until a small, rough chop forms. You'll need to do this in batches and transfer the ones you've done into a bowl

Once all of the vegetables are processed and stirred together, return to the food processor with the salt and process until a thick wet paste forms but individual bits of vegetables remain distinct

Transfer to very clean storage containers and freeze. Because of the salt, the bouillon will be very easy to scoop out a spoonful at a time

To use, mix 1 teaspoon of bouillon with 240mls water for a delicious soup stock. Makes around 200 teaspoon servings