This week, a handful of New York chefs have added snack-sized, easily portable items to their early autumn menus. The new treats, which include sticky rice cakes and chocolate-dipped fruit clusters, have a common warning: do not stash them in your jacket pocket. At a Thursday lunch service at Popina in Cobble Hill, servers gently reminded diners about the hazards of melted chocolate in wool coats.

The city’s first hints of cooler weather have prompted a shift toward hand-held, comfort-driven snacks. At Win Son Bakery on Jefferson Street, a cook described a surge in requests for their sesame-studded pastries. "People want things they can take outside," she said, “but some of these don’t travel well.”

Cooks say the new wave of snacks is meant to be playful, but not at the expense of practicality. At Barney Greengrass on the Upper West Side, a manager pointed out the mess left behind by a customer who tried to carry a hot knish in a blazer. On Thursday morning, a teacher from a nearby school ordered five to-go, but left with a paper bag in hand—not trusting her pockets.

As the city’s public schools reopened this week, more residents are eating on the move. Bakeries near subway stops reported steady sales of crumbly cookies and sticky buns. Still, staffers warned customers that some options—especially those with caramel or fruit fillings—are best eaten immediately. The city’s autumn snack trend is easy to embrace, as long as diners keep the mess in mind.