Remove the basil leaves from the stems; gently wash the leaves under cold running water; do not fold them as they turn black easily.
Spread the leaves onto a tea towel and dry them. They must be perfectly dry to make pesto.
In a mortar, crush the garlic with some salt.
Add the basil along with all the ingredients except the oil.
Lightly toast the pine nuts in a skillet on the stove top for a few minutes until they turn golden brown (stir constantly); this will make a nuttier taste.
Crush a few leaves of basil, adding only a few leaves at a time with long circular movements of the pestle until there’s a smooth and even paste.
After crushing the basil, add the crushed garlic and pound the mixture until evenly blended. Add the cheese.
and then the oil to bind the sauce and create a creamy paste.