Preheat oven to 180°C.
Mix the flour, brown sugar and bicarbonate of soda together.
Add the cinnamon and salt and mix well.
Beat the eggs, butter and essence together and add to the dry ingredients.
Mix well until smooth.
Add the remaining ingredients to batter and mix lightly.
Spoon equal amounts of batter into a greased muffin pan and bake in oven for 20 minutes.
Allow to cool in pan before turning out onto a wire rack.
Pour a little rum over each muffin while still warm.
Serve warm with cream.