Step 1

When buying basil, look for a bunch that is fresh and has a good aroma. Basil is best used immediately as it is quite perishable. To store it, wrap in paper towel or a dry tea towel and place in a sealed plastic bag or airtight container in the fridge for up to 3 days.

Step 2

Place pine nuts, garlic, salt and half the basil in bowl of a food processor, and process until basil is roughly chopped. Add remaining basil and process, using a spatula to scrape down the side of the bowl occasionally, until all the basil is finely chopped and the mixture is well combined.

Step 3

With the motor running, gradually add the oil in a thin steady stream, scraping down the side of the bowl occasionally, until all the oil is incorporated and the mixture is well combined. It is important to add the oil gradually so the pesto forms a paste and the mixture doesn't separate.

Step 4

Stir in the parmesan. Use good-quality parmesan when making pesto, as it will affect the flavour and freshness. Buy a piece of parmesan and grate it rather than purchasing pre-grated parmesan to ensure the best freshness and flavour.

Step 5

If you aren't using the pesto immediately, transfer to a small airtight container or jar. Pour a thin layer of olive oil over the top of the pesto to help prevent it from discolouring.