My mum began making pesto in the 70's when we lived in Italy. It has always been a rare treat in the summer when the basil plant had enough leaves, and pine kernels were plentiful and relatively cheap. The adult me, and our growing family, moved to Alresford in Hampshire in 2004 the self styled 'Watercress Capital of the World'. With watercress 60p a bunch I soon developed a more Anglicised and all year round pesto.
Watercress, Walnut & Cheddar Pesto
1 bunch or bag of watercress, washed
1 small clove of garlic
1 handful/50g strong cheddar
1 handful/50g walnuts
2 tbsp olive or sunflower oil
Squish all the ingredients into a mini food processor and blend until smooth. Add more oil one teaspoon at a time if necessary to make a dip consistency paste.
This quantity serves 4 people as a pasta sauce. I'm sure there are other uses for it but we never have any left over.