Preheat the oven to 180°C/160°C fan oven/gas 4. Line a 12 hole muffin tray with cupcake cases.
Sift the flour, Baking Powder and mixed spice into a bowl. Stir in the sugar and pecan nuts. Make a well in the centre. Gradually, using a wooden spoon or electric hand mixer, mix in the eggs and oil to form a smooth, thick cake batter. Finally stir in the grated carrot.
Divide the mixture equally between the cupcake cases. Bake for 25-30 minutes lightly golden and a skewer inserted into the centre comes out clean.
Pop the butter and icing sugar into a large bowl and beat together using an electric hand whisk or freestanding mixer with the beater attachment, until smooth and combined – make sure there are no lumps of butter. Pop in the Vanilla Extract and cream cheese and beat together until you have a lovely light and fluffy buttercream.
Once the cupcakes are cooled; pop the icing into a piping bag. Pipe a swirl of icing onto the top of each cupcake and finish with a sprinkle of chopped pecans!