Tis the season... polo potluck

Sacla Classic pestoThe problem with all pesto is that it contains Parmesan, and, like our old friend the Mars bar, Parmesan is not made with vegetarian rennet, but the icky stuff out of calves' stomachs. There is no such thing as vegetarian Parmesan, though there are several cheeses that look and taste passably like it, such as Twinham Grange. Think of it like that Naomi Campbell lookalike who got into lots of nightclubs for free because she looked the spit of Naomi. Only with cheese.

From some guardian food page.