Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4 and line a cupcake tin with 12 paper cases
In a large bowl whisk together the light brown soft sugar, eggs and vegetable oil
Add the pumpkin puree and whisk in
In another bowl stir together the self raising flour, baking powder, salt and all of the spices - cinnamon, ginger, nutmeg and mixed spice
Add the flour mixture to the pumpkin mixture and whisk them together
Divide the mixture between the cupcakes cases, and bake them for 20-25 minutes until they are golden brown and a thin skewer or cocktail stick inserted in the centre comes out clean. Put them on a cooling rack to cool completely
To make the buttercream, mix together the butter, cinnamon, vanilla extract, milk and icing sugar with an electric whisk until smooth. If the buttercream is too stiff then you can add some more milk to it
Pipe the buttercream onto each cupcake using a piping bag fitted with a nozzle (I used Wilton 2D). Or spread it on with a spoon
Add fondant pumpkins or sprinkles if desired, then serve! Leftovers will keep in an airtight container in a cool place for 3 days