To 1/4 pound of raw young leeks, add 1/3 jar of pine nuts (scant 1/4 cup) and enough EVOO or sunflower oil to process (1/4 to 1/2 cup - leeks are thirsty). Process until smoothish.
It won't be "super smooth", but that's okay.
I grated 2.5 ounces of hard cheese in a bowl - I used our Connor Abbey, but parmesan will do fine. The cheese can be added in the processing step if you like, but my KitchenAid is quite wee so it's easier to add it separately. Adjust for salt - it won't take much to balance the sweetness - or you can leave it as is, if that is your preference.
This recipe makes about 1 1/2 cups of pesto, which I divided into two snack-sized Ziploc bags and froze - though, the following day I was already contemplating defrosting one. Yummy! So good, I'll say it again, "Yummy!"