Strip the leaves form the parsley and mint and whizz in a food processor or blender with the garlic until roughly chopped
Add the lemon zest and walnuts and whizz again for a few seconds. Finally, add the oils, compote and chilli, if using. Process to a rough paste.
Spoon the paste into a clean jar. Pour on a little extra olive oil to cover the surface of the pesto and keep in the fridge until needed.