Mom's pesto is the best! See the notes for all her tips.
1. Genovese basil with corrugated leaves is more flavorful than lemon basil with flat leaves.
2. The basil must be air dried to ensure the leaves are completely dry, in order to achieve the right texture.
3. If you don't have a scale to weigh your basil, you can fill up a 2-cup liquid measuring cup twice with packed basil until it's heaping.
4. Imported Pecorino Romano (made from sheep's milk) is key for flavor. You can buy it at an Italian import store or online.