It's been a while since I've made - or even come across - any whoopie pies, once touted as the 'new cupcake', so when the letter W came up for this month's Alphabakes, I thought it would be a great thing to bake.I have a recipe book entirely dedicated to whoopie pies, called - originally enough - The Whoopie Pie Book, by Claire Ptak of Violet bakery. Flicking through, I came across the perfect bake for a triple W whammy - the Walnut Whip Whoopie! I don't know if anyone outside the UK has had these, they are a chocolate pyramid filled with marshmallow with a walnut half on top. They were my grandmother's favourite and are absolutely yummy!Ingredients:300g plain flour1 tsp bicarb of soda1/2 tsp salt125g butter, softened200g sugar1 egg1 tsp vanilla flavouring200ml buttermilk100g walnuts, ground, plus extra for decorating100g ground almondsWhoopie pies are fairly simple to make: mix flour, bicarb of soda and salt and set aside. In a separate bowl, cream the butter and sugar, add egg and mix well. Grind some walnuts Mix the buttermilk and vanilla and add half to the butter mixture. Slowly mix in the dry ingredients other than the nuts. Pour in the remaining buttermilk and mix, then fold in the nuts. Chill the mixture for 30 mins.Place a spoonful into your whoopie pie tin (thanks David!) or onto a baking tray. Bake for around 10 minutes and leave to cool.I did attempt to make the vanilla swiss buttercream recipe from the book, which involves whisking egg whites, sugar and golden syrup over a pan of simmering water, but I obviously did something wrong as the mixture stayed really runny and I couldn't use it to sandwich the whoopie pies together. I took some pretty pictures anyway :-)In the end I resorted to a standard buttercream to sandwich the whoopie pies together. To make them look like walnut whips, I piped a small swirl of chocolate buttercream on top and placed a walnut half on top.I took these on a picnic with my boyfriend's family and friends - which was eaten largely huddled under coats and blankets as the weather was rubbish, but we were there to see an outdoor concert and by darn it, we're British and that's just what we do! Anyway, these would also be good for a bake sale as they are individually portioned, so I am sending this in to Tea Time Treats as their theme for June is cake stall cakes and bakes. This month the challenge is hosted by Karen from Lavender and Lovage; her co-host is Kate from What Kate Baked.As it's a triple W whammy I'm also sending it into Alphabakes, which I am hosting - our letter this month is W, and there's a prize (only available for entrants in the UK). Check out the rules here if you fancy taking part!