In a mixing bowl, combine the cornichons, parsley, chives, dill, and aioli. Mix well.
Add the dijon mustard, lemon juice, and lemon zest to the bowl. Stir until fully incorporated.
Season with salt and pepper to taste. Adjust lemon or mustard if needed.
Refrigerate for at least 30 minutes to allow the flavors to meld.
Notes
Storage: keep in an airtight container in the fridge for up to 4 days. It's built on aioli, so give it a stir before serving since it can separate slightly.