METHOD
1. Mix all the ingredients under cake to form a smooth batter, for 1-2 minutes
2. Line a standard 12 hole muffin tray tin with muffin cases.
3. Divide the mixture between the muffin cases.
4. Bake in a preheated oven 180°C (360°F, Gas Mark 4) for 20-22 minutes until firm to the touch.
5. Allow to cool completely before decorating.
6. Place the stout into a saucepan, simmer over a low heat for 10-15 minutes until it has reduced to a thick syrup. Allow to cool.
7. Sift the icing sugar into a bowl and add the butter,
8. Beat until smooth and creamy for about 4-5 minutes with an electric whisk or machine, then add the reduced stout and mix well. Do not over beat or the mixture may become runny.
9. Pipe the icing over the cupcakes and decorate with chocolate curls or cocoa powder.