Add the sea salt and a few of the basil leaves to your marble mortar. Using a wooden pestle, crush the leaves and salt gently but with a firm rhythm against the bottom and sides of the mortar so that the leaves gradually come apart. Keep adding leaves a few at a time until they are all used. While the leaves are still partly intact, add the garlic and then pound it too, just until it is mashed and has released its juice. Then add the pinoli and pound them until they are reduced to paste. Stir the pestle in the mortar so that the ingredients combine. Then add the Pecorino Romano and Parmigiano-Reggiano and stir again to combine the ingredients. Now add the olive oil a little at a time, stirring with the pestle to make a sauce of a creamy consistency. Some people like more oil, some less, so the amount I recommend is a guideline. Your goal is to have a thick creamy sauce. If you choose not to use all of the oil, that is fine. The result should be fully amalgamated and of a medium bright green color.