Add the garlic and salt to a pestle and mortar and crush it into a fine paste.
Add the basil leaves in batches, one handful at a time. Crush each handful in turn in the mortar until the leaves are broken down the the oils have released.
Once the basil leaves are all crushed, grate the cheese and add it in too. Crush again to incorporate.
Toast the pine nuts over a hot pan for 30 seconds to a minute. They will go a nice brown colour and smell very aromatic. I think they smell a bit like popcorn.
Add the pine nuts to the mortar and grind into the paste. You want them to be mostly broken down and smooth, but with some coarse bits remaining.
Finally, pour in the olive oil gently while mixing with the pestle to combine into a smooth pesto and serve!
