Peel and chop the root parsley and onion.
Put the lentils in a pot with water together with the root parsley and the finely chopped onion.
Let the whole simmer for 30 minutes.
Then pour off excess water.
Put the mixture in a blender and blend until smooth. You can also use a puree stick. Add a little water if necessary. Mass should not be too soft.
Pour the mixed mixture back into the pot.
Stir in tomato paste.
Mix tapioca starch with 10 ml cold water.
Add tapioca starch as well as locust bean gum to the pot.
Bring everything to a boil together.
Stir in the basil and the spices.
Season the whole thing to taste.