The Pasta Alla Genovese has both ordinary and extra virgin olive oils, but does not say at which points each should be used?
The sauce is similar to a pesto but doesn't contain any pine nuts. Nigella uses a combination of regular and extra virgin olive oil as extra virgin oil on its own can slightly overwhelm the other flavours. Both oils are added at the same time to the food processor, along with the basil leaves, Parmesan and garlic (see step 3 of the method). You could use all extra virgin olive oil for the sauce, if you prefer.