Since I prefer to use skinless almonds, I soak the almonds overnight or for a few hours in warm water which helps to easily peel off the skin. Alternately you can also use crushed or almond flakes if you have that on hand.
In a blender/processor, add the rocket leaves, almonds, garlic, chilli and blitz for a minute.
Scrape the sides and add the parmesan and half of the olive oil. Blitz again for a minute.
Add more olive oil if necessary and blitz again to get a thick chunky sauce like consistency.
Notes
Freeze the leftover pesto in airtight containers; keeps for 3 months