Why cake bakers are making whoopie

Cupcakes, shmupcakes. The latest patisserie trend that has piped its way over from the States to our shores comes in the form of two squidgy biscuits stuck together with buttercream and marshmallow fluff.

The whoopie pie (also known as the giant Oreo cookie because of its similarity to the American biscuit) has enjoyed a resurgence in America since Manhattan's Magnolia Bakery began stocking them - in the same way that Carrie Bradshaw and co made cupcakes popular by gorging on the iced delicacies from that same cake shop in TV show Sex and the City.

Marks & Spencer rolled out its version at the beginning of May and had to bring in extra supplies to meet the huge demand. Available in a triple pack of vanilla, chocolate and toffee, they are sold in packs of four for £1.99. "Whoopie pies are to 2010 what the cupcake was to 2009," says the store's product developer Chris Seaby. "We brought the launch forward two months because we knew they would be popular, but the response has been phenomenal."

Like the cupcake before it, the whoopie pie is much more fun than all the serious - albeit tasty - tea-time treats Britain has produced over the years (flapjacks, scones and Eccles cakes, anyone?), so it is no wonder our bakers are following suit.

The whoopie pie, said to date from the 1920s, was first made by Amish farmers' wives from leftover cake batter as a lunch-time treat for their husbands, who ploughed the fields of Pennsylvania. When they spied the cakes in their lunch packs, they would shout: "Whoopie!"

Since then, they have become a staple in the American sweet cupboard. They even have an annual festival held in their honour in Pennsylvania.

Natalie Allen of Sweet Things (www.sweetthings.biz) is one of a small but growing number of UK outlets - including the Hummingbird Bakery and Harrods - which started selling whoopie pies before M&S cottoned on. Retailing at £1.75 each, she reckons her sweet pies will take over from the cupcakes as the last word in sweet trolley-chic at barmitzvahs and wedding anniversaries.

"I always look to American websites to see what the latest trends are over there," says Allen, who supplies posh food hall Fortnum & Mason and whose brownies are a favourite with Nigella Lawson. "That way, I get them before they reach the UK. I had absolutely no idea what they were so I had to do some research. I always describe them as a cookie sandwich. They're totally different to a cupcake. They have quite a salty, sour sponge. When people see them they say, 'Oh wow, what's that?'"

Allen does just the original flavour - chocolate - with a gooey vanilla cream in the middle. The lightness of her sponge is due to a batter is made with bicarbonate of soda and not baking powder, which is crucially different to the cupcake. And there we all were thinking that raising agents were interchangeable.

The icing - or frosting as they call it in the States - is made with an American confectionary item that comes in jars - Marshmallow Fluff. That, and the lack of egg, makes it lighter than regular butter cream. To finish, Allen adds just a sprinkling of glitter on top, rather than what she believes would be a cloyingly sweet icing. The overall experience is one that is neither too sweet nor too filling but full of American style flavouring.

The whoopie pie certainly has advantages over its prim cupcake friends. Rather than getting the (often copious amounts of) icing up your nose before reaching the cake below as you do with a cupcake, the cream in a whoopie pie is neatly contained within the two mounds of cake - rather like the meat in a burger. And they are much less fiddly to make if you keep them simple, which is the way they are supposed to be.

But of course, some places just cannot help making things more elaborate. The Hummingbird Bakery has turned its whoopie pies into a posh affair with red velvet and pumpkin flavoured sponges both with cream cheese filling varieties going from £3 each. Harrods does a cherry fondant flavour decorated with silver pieces and cherry hearts. Theirs are £2.50 each.

Where Harrods leads others follow so it will not be long now till everyone is making whoopie.