Fall in love with this easy recipe for whoopie pies. Two light discs of chocolate sponge sandwich a fluffy vanilla buttercream filling. Perfect for cake sales, packed lunch treats or making friends at the office!. Heat oven to 180C/160C fan/gas 4 and line baking trays with parchment. Mix flour, cocoa, bicarb, sugar and a pinch of salt. Whisk the egg, oil and buttermilk together, then mix into dry ingredients with 75ml boiling water.. A bit too big for a whoopie pie, and the fondant icing on top is unnecessary and very DIY, but an overall delight, especially the tangy filling. Harrods (£2.50 each, or £1.25 for a mini whoopie . KAISER 12-Cup Whoopie Pie Baking Pan 38 x 27 cm Creativ Very Good Non-Stick Coating Short Baking Time for Sweet and Savoury Recipes. . .