Gently wash the basil leaves, paying attention not to crunch them.
Lay the basil leaves onto kitchen paper and let them to dry. DO NOT press or pat the leaves with kitchen paper but leave them to dry naturally.
Cut the clove of garlic longways through its centre, remove and dispose the shoot. Then, roughly chop the clove into a few pieces.
Firstly, add the pine nuts. The reason we process them first is that they require more time and a high speed to break up properly. We do not want to add the basil at this stage otherwise it will be over blended and the heat generated by the friction may alter the colour and fragrance of the basil.
Once you have blended the pine nuts, add the basil leaves into the blender jug.
Also, add the garlic.
Start blending, at low speed (if you can adjust the speed of course), and at the same time gradually pour in the olive oil.
Add a small quantity of salt to season.
Add the Pecorino sardo cheese.
Add the Parmesan cheese.
Now, blend again for a few seconds and then you will have your pesto sauce.Put the pesto into a large bowl, add a spoonful of the boiling water you are using to boil the pasta and then add your drained pasta into the bowl. Stir for few seconds until the pasta is evenly coated and serve.