Combine basil leaves, pine nuts, garlic, and cheese in a food processor and process with a blade attachment until well blended.
With the food processor running, slowly drizzle the oil until you get the consistency you desire.
Taste the pesto and add part or all of the salt according to taste.
Notes
Pesto freezes very well. Try freezing it in ice cube trays so you will have perfectly portioned amounts to add to vegetables, pasta, sandwiches and dips.