Mince the parsley until you have enough to make up ½ cup and do the same with the cilantro. Add the minced herbs to a medium sized bowl.
Mince the shallot and garlic cloves and add to the bowl.
Slice the chilli in half lengthwise. If you prefer a milder spice to the sauce, remove the seeds before mincing. If you like it spicier, leave the seeds in. Add the minced chilli to the bowl.
Add the remaining ingredients to the bowl and whisk until thoroughly mixed.