Roughly chop parsley leaves and stems. Place almonds, tomato paste, parsley, garlic and a generous pinch of salt in the bowl of your food processor.
Process for 1-2 minutes or until everything is very finely chopped and coming together as a thick paste. Scrape down the sides then puree for another few seconds.
Add oil and stir in manually (or pulse with the food processor) - I find the flavour better when I stir.