For a Diwali treat with an American twist, a new cookbook serves up cardamom-spiced carrot blondies

By ALBERT STUMM

Every year for Diwali, Hetal Vasavada’s parents used to pull her out of her New Jersey elementary school to visit friends and family living nearby.

The colorful South Asian holiday is the Hindu Festival of Lights. For some, it also marks the start of a new year, and observers believe that what you do on Diwali sets the tone for the rest of year.

In that spirit, Vasavada’s family made sure to wear their best new clothes and to wake up to a clean house. And they always brought sweets...