Pour vegetable or olive oil in the pestle and mortar and mix it together. For food processor pour oil through the feed tube to make a paste. Season to taste with salt and pepper. (The pesto can be refrigerated in a covered container, with a very thin layer of vegetable oil poured on top to seal the surface, for up to 2 weeks, or frozen for up to 3 months. Bring to room temperature and stir well before using.)