Preheat the oven to 190oc/170oc fan and line a 12 hole muffin tin with cupcake cases. In a bowl, whisk together the flours, bicarbonate of soda, spices and sugar then set to on side. Crack the eggs into the oil and whisk together before pouring into the dry ingredients with the carrots. Fold to combine until the mix is well incorporated then add the orange zest, juice and pistachios and stir again. Divide the mix between the cases then bake for 20 to 25 minutes until golden brown and a skewer inserted in the middle comes out clean. Cool in the tin for a few moments before cooling completely on a wire rack.
To make the buttercream, beat the butter in the bowl of stand mixer or large bowl if using a handheld mixer for around two to three minutes until it has turned very pale, whipped and creamy. Add half of the icing sugar and slowly combine together to stop the sugar puffing out of the bowl, then beat on high for around a minute until fluffy and smooth. Add the remaining icing sugar and repeat, increasingly the speed and beating until the buttercream is pale and fluffy. Add the vanilla and a splash or two of milk to loosen the mixture (almond gives the buttercream a nice nutty taste) and beat again to incorporate. Spoon into a piping bag fitted with a star nozzle and twist the bag at the end.
Once the cakes are completely cool, hold the piping bag vertically over one cupcake and trace around the outside of the cake with the icing, swirling inward until you reach the middle, easing off the pressure and pulling up sharply. Repeat with the rest of the cakes and finish with a sprinkle of pistachios.
Recipe by Victoria Sponge Pease Pudding at http://victoriaspongepeasepudding.com/baking/pistachio-and-carrot-cupcakes-and-a-video/