Two saucer-shaped rounds of chocolate cake sandwiched around a marshmallow-y cream filling: that's the classic whoopie pie. Originally popular in New England and around Amish country, the whoopie pie has gradually been spreading throughout America, and for good reason: it's a delicious throwback to the days before everyone started counting calories or fat grams. Consider these an occasional decadent treat. . Tips from our bakers. To make 16 smaller whoopie pies (about 2 3/4" dia., about 2 1/2 ounces each): drop the dough onto the baking sheets in 30g balls, about the size of a large ping pong ball, or about 1 1/4".. #HowItsMade Mondays 9/8c on Science This Whoopie Pie factory has a variety of delicious ingredients that give these traditional treats their signature taste..