Ingredients 
Cake Ingredients 
40g room temperature butter
100g plain flour
25g cocoa powder
1½ tsp baking powder
140g caster sugar
1 large egg
120ml milk
1 tsp vanilla extract

Icing
200g icing sugar
25g cocoa powder
75g room temperature butter
25ml milk
¼ tsp vanilla extract

To Decorate
Smarties, jelly tots, mini pretzels, mini flakes, silver balls, hundreds and thousands, glitter, gold stars etc etc etc!

Method
Heat the oven to 180c.

Put the butter, flour, cocoa powder, baking powder and sugar either in a mixer with paddle attachment or large bowl for an electric whisk or just with a wooden spoon.  The wooden spoon works fine, it just takes a few minutes more.  When my Saturday cooking club made these none of us used the mixer.  Work the butter into the dry ingredients until it looks like fine breadcrumbs.

Put the both the egg and the vanilla extract into the milk and mix.  Pour half of the milk mixture into the flour mixture and mix, when incorporated add the rest of the milk and mix. 

Line a cupcake tin with cupcake cases and fill each case with two thirds of the mixture.  I like to use an ice cream scoop as it is the perfect amount. Cook for 20-25 minutes.  Cook until the cake feels firm and a skewer comes out clean.

If you have a fairy cake tin and fairy cases which are slightly smaller these can be used, they will just cook quicker so will only take 12-15 minutes.

While the cakes are cooking, make the icing.  Again this can be done by machine or hand.  Sift the icing sugar and cocoa powder.  Put the butter into the bowl - if you are doing this in a machine put all of the icing sugar mix in and mix on a slow speed until incorporated.  If you are doing by hand put in a third the icing sugar mix in and carefully mix through before adding another third, completely mix in and then add the last third.

Add the vanilla extract to the milk and add to the icing bit by bit.  Once all is added, beat until light and fluffy. 

When the cupcakes are cooked, get them out and leave them to cool completely.

To decorate… either spoon or pipe the icing on the top and decorate how you like, for a reindeer use brown smarties for the eyes, a red smartie for the nose and pretzels for the antlers - chocolate pretzels are lovely but a curly whirly will also work.

For a tree, cover two thirds of the flake with icing and then push the un-iced part into the cake and use green smarties or jelly tots to make your green tree.

Variation:
For vanilla cupcakes, instead of 100g flour and 25g cocoa powder, just use 125g flour in the cupcakes. For the icing use 175g icing sugar, 60g room temperature butter, 15ml milk, ¼ tsp vanilla extract.

For marble cupcakes, use 125g flour, half fill your cupcake cases and then add 2 tbsp cocoa powder and thoroughly mix and top up your cupcake cases. Take a skewer and put into your filled cupcake case and gently swirl to create your marble effect.
For the icing use 175g icing sugar, 60g room temperature butter, 15ml milk, ¼ tsp vanilla extract. Take out half of the icing and add 2 tbsp cocoa powder and mix. You can now put both into a bowl and swirl together to get the marble effect.