- Place herb leaves, zest of one lemon and juice of 3 lemons into the bowl of a food processor or mortar. Process well to chop. Add almonds and process until well blended - this may take a few minutes.
- With the motor running, or while pounding continuously, drizzle in enough oil to form a dense paste. More or less oil can be added depending on the thickness of pesto required.
- Season to taste with salt and pepper. This pesto lasts for up to one week if stored covered in the fridge. Serve as a dip or spread.