Add ingredients to a blender or food processor, except the olive oil.
Slowly drizzle in the olive oil as you blend the other ingredients.
Store in a container with an airtight lid, or follow the tips below to freeze your pesto.
Video
Notes
To Store
Refrigerate - Transfer it to an airtight container. Add a layer of olive oil to help keep it fresh longer. Olive oil prevents the basil from coming in contact with air, preventing it from oxidizing. It will keep in the refrigerator for up to a week.
Freeze - Pesto sauce freezes so well, I often make a big batch when I have leftover basil. Freeze it in an ice cube tray (or sheet pan) and then transfer to a freezer bag. Frozen pesto keeps well for up to 6 months. You can defrost the cubes in the fridge or stir the cubes directly into hot pasta.
To Retain the Color - Simply blanche the basil prior to making to keep the basil pesto bright green. As it oxidizes, pesto darkens (which doesn't phase me a bit!)