There are all sorts of variations on this traditional basil pesto (pesto alla Genovese) and you can substitute rocket, spinach or even wild garlic leaves for the basil.
Fresh pesto tastes the best but if you have made too much (or you are trying to use up a glut of herbs) it will keep for a week or so in the fridge in an airtight container – you may want to pour a little extra olive oil over the top to help preserve the flavours.
You can also freeze pesto where it will keep for around six months. A simple way to do this is to put the pesto into an icing bag and pipe it into ice cube trays – that way you can always thaw the perfect amount.
The quantities of ingredients in pesto don’t have to be precise – it’s really down to personal taste but this approximates the ingredients I use.
1 medium sized clove of garlic, chopped
3 generous handfuls of basil leaves, removed from the stalks
1 handful of pine nuts
1 handful of finely grated parmesan cheese (it tastes much better if you buy a block and grate it yourself)
Extra virgin olive oil
A squeeze of lemon juice
When I have time I like to make this in a mortar and pestle – when I am rushed or feeling lazy I use the food processor instead. Experiment and see what works for you.
Lightly toast the pine nuts in a frying pan over a low heat.
Chop the garlic and put it in the mortar with a pinch of sea salt. Grind until smooth using a circular motion and firm pressure.
Add the basil and grind some more until you have a green paste.
Add the toasted pine nuts. Continue grinding until combined and reasonably smooth (a bit of texture is nice).
(Or put garlic, basil and pine nuts in a food processor and pulse until combined.)
Transfer to a bigger bowl if necessary, then stir in half the parmesan and a good glug of olive oil.
Add more parmesan and olive oil until you have the consistency you want.
You probably won’t need more salt (the parmesan is salty) but season to taste with freshly ground black pepper and a splash of lemon juice.