To prepare the nettles
Wearing rubber gloves to avoid getting stung, wash the nettles thoroughly and remove any thick stems.
Bring a big pan of salted water to the boil then add the nettles. Blanch them for around a minute to remove the sting. Then use a colander to drain them and rinse them under cold running water.
Squeeze the nettles to remove as much water as possible then chop them up roughly.
To make the pesto
Add the pine nuts and walnuts to a food processor and pulse for a few seconds. (If you don’t have both, it’s fine to use 100 g pine nuts or 100 g walnuts.)
Add the chopped nettles, garlic, lemon juice, salt and pepper, and nutritional yeast if using. Mix for a few seconds then add the olive oil and water. Add more water if you like your pesto a bit thinner.
Stir through freshly cooked pasta or enjoy as a dip or spread.