Preheat oven to 180C. Line a 12-hole medium-size muffin tin with paper cases.
Beat softened Butter in a mixing bowl with a whisk until smooth. Add Sugar and beat until creamy.
Add Eggs, one at a time, beating well after each addition. Add Rum or Vanilla, gently fold in Flour with a spatula or a large metal spoon, add Milk and chopped Chestnuts as well, and mix until just combined. DO NOT over-mix.
Spoon the mixture into paper cases. Bake for about 20 minutes or until golden and cooked through. Leave in tins for 5 minutes before moving onto wire rack to cool.
To make Chestnut Cream, combine Sweet Chestnut Paste and Rum, then add to the whipped Cream and mix well. Decorate the cooled cupcakes with the Chestnut Cream.
