This recipe can be doubled, but don't triple it, since the basil may not puree completely. If you need larger quantities, make it in batches. The flavorful oil is best made the day it will be served, when the basil is still bright and fresh.
Place all ingredients in a blender or food processor, and process until smooth and combined. Transfer to a glass jar or airtight storage container, and keep at room temperature until ready to use.