Preheat the oven to 170C Gas Mark 3
Cream together the butter and sugar until fluffy
Mix in the rest of the ingredients until well combined and smooth
Share the mixture between 12 cupcake cases
Bake for 20 minutes until firm
Leave to cool
To make the icing mix the butter and sugar together until fluffy, adding a little milk if needed
Add the treacle and stir until combined
Top each of the cakes with the icing.