To make the sponges, add the butter cut into cubes to a pan set over a low heat.
Add the syrup, treacle and brown sugar, and mix gently until the butter melts and we get a smooth mixture.
Remove from the heat and leave to cool.
In a large bowl, sift the flour, add the ginger and spices.
In a separate bowl, beat the eggs well, add the milk, and mix again.
Pour the egg mixture over the cooled butter mixture, and mix.
Combine the dry ingredients to the wet ingredients, and give it a good stir for the batter to be fully incorporated.
Line a muffin/cupcake tin with paper cases, and divide the mixture evenly.
Bake at 190 degrees Celsius (375 Fahrenheit) for 20-25 minutes until the cupcakes are set, and a skewer inserted in the middle comes out clean.
Leave to cool completely.
To make the icing, add the butter and icing sugar to a food processor, and blitz.
Add the vanilla extract and milk, and blitz again to get a smooth paste.
Use a piping bag with the nozzle of your choice to pipe out the icing.
Decorate with sprinkles - optional.