Add basil leaves, green chilli, garlic cloves, parmesan cheese and cashew nuts in a chopper or food processor and blend the ingredients. Keep the texture as required. I like to coarse pesto.
Add olive oil and blend for few more seconds, add salt as per taste.
Store pesto in an air-tight container. Stores well for a week or up to 10 days in the refrigerator. It can also be frozen for few more day. Freeze in ice-cubes and then transfer to the ziplock bag bags. USe as required in soups, pasta or pizza and salads.
Notes
I added one green chilli for the spice factor. We Indians love some spice factor in our chutneys, dips or spreads. You can leave that or add some chilli flakes.