New Delhi, July 27 -- I walk past the ice-cream display freezer at La Michoacana in Kennett Square, a borough in Chester County, Pennsylvania, US. Those are some unusual flavours: rice pudding, avocado, tamarind and corn (dusted with chilli powder). But there's one that seems out of place: mushroom. I decide to give it a try since I'm in the "mushroom capital of the world". The earthy, subtly nutty ice cream surprises me: it has a creamy texture, a hint of umami sweetness, and an almost caramelised mushroom undertone. The scoop shop owner smiles; she's seen that look of surprise many times.

Kennett Square sits in the heart of lush Brandywine Valley. Here, mushrooms aren't just food; they're an identity. Shops in the quaint town are dedic...