Chop the basil leaves. Put into a large mortar with the salt and minced garlic.
Crush the pine nuts - putting them between two sheets of waxed paper and then rolling with a rolling pin makes light of this step. Add to the mortar.
Pound, pound, pound, using a grinding motion and being sure to include anything that sticks to the sides of the mortar.
When a thick paste has formed, add the cheeses and pound again, just to incorporate the cheeses. Add the olive oil, a tablespoon at a time and pound/grind some more until oil is fully incorporated. The amount of oil will vary with other ingredients (see our pesto article).
Put pesto in a jar and let settle. Oil may rise to the top, but if not, add a thin film of oil on top to preserve and keep that lovely basil fresh. Refrigerate.