Whoopie pies part of northeastern cuisine

"Whoopie Pies"

By Sarah Billingsley and Amy Treadwell

(Chronicle, $16.95)

The whoopie pie does not exist in nature.

It is indigenous to the Northeast; in particular, to Maine, and Amish regions of Pennsylvania. Its true-true habitat, however, to be GPS-precise, is within small baskets, plastic wrapped and tucked beside cash registers in gas stations and general stores, from Nova Scotia to seasonal grocery stops on Block Island to rural patches south of Connecticut, into the country estates of suburban Philadelphia.

The lore, as Sarah Billingsley and Amy Treadwell explain in "Whoopie Pies" (Chronicle, $16.95), their cute celebration/cookbook, states Amish schoolchildren would open lunchboxes, find the moist treats inside and shout "whoopie!" Which is probably true, as that story sounds less likely with a salty New England clammer.

The whoopie pie is not pie. It is two plump, rounded, usually chocolate cakes sandwiching a white wad of sweet (occasionally marshmallow) frosting; its closest kin is the Hostess Ding Dong, though Billingsley and Treadwell, on the cusp of the whoopie's cupcake-like ubiquity, offer suggestions for chocolate ganache filling, a salted caramel filling, even a savory bacon-chive goat cheese filling, which is enticing, though it would have been sacrilegious to the original 13 colonies.