Preheat oven to 180 degrees Celsius. Add 16 cupcake cases into a tin.
Beat together the butter and brown sugar until light and creamy. Beat in the molasses and eggs until well combined.
Sift in the flour, baking soda, spices, Colman’s Mustard Powder, and salt. Mix until smooth.
Pour the batter into the prepared cases and bake for 20-25 mins, until a skewer inserted in the centre of the cupcake comes out clean.
Cool on a rack. Top with vanilla icing.