I add chickpeas. They add good texture to the pesto as well as a little nutty flavor.

Toasted bread crumbs would make a great substitute, try panko (Japanese style crumbs), gently warmed in a pan till lightly brown. You could also add some lemon zest

My husband, who also suffers from nut allergies, is allergic to certain types nuts. Pine nuts do not bother him at all, while other nuts do. You want to inquire with your guests as to what specifically they are allergic to. You may choose that it is better to be safe than sorry and omit them from your recipe all together. Flavored oil are a great option for adding depth of flavor.

Good pine nuts (not from China) are hard to find these days, and SO expensive. I don't like walnuts in Basil pesto, so I just leave the nuts out altogether.

If someone's allergic to pine nuts, another crunch could be unsalted sunflower seeds. They remind me of pine nuts, especially in texture.

My husband is allergic to all tree nut but not seeds so pumpkin, sunflower seeds and pine nuts are ok for him. It really depends on a persons specific allergy so it is best to just leave them out unless you check.

Are pine nuts in the same class as walnuts, almonds, etc? And how about cashews -- they grow completely differently from other "nuts"?

Mmmm. Pumpkin seeds sound wonderful. I must be on your guest list. I'm allergic, too, and just leave them out and bulk up on the cheese. Never thought about a seed substitution, and it does sound really, really good. I'll try that next time.

If you prefer the texture that comes from having the nuts, you could also try making it with sunflower or pumpkin seeds. It would change the flavor profile a bit, but it might be delicious.

Agree with first two answers! My son has a severe nut allergy and I just leave them out.

Yep! The French equivalent, pistou, does not include nuts. Just taste and see what you think. I agree with Amanda, a little extra cheese might be in order.

Yes -- in fact, pesto doesn't need nuts. Just leave them out, and if desired, add a little extra cheese.