1. Preheat the oven to 170 degrees Celsius and line a roasting tin (30cm x 20cm x 5 cm) with baking parchment.
2. In a saucepan, melt the butter, golden syrup, black treacle, ground ginger and finely chopped stem ginger, cinnamon and cloves over a low heat.
3. Remove from the heat and add the milk, beaten eggs and dissolved bicarbonate of soda in its water.
4. Stir to combine all the ingredients.
5. Sift the flour into a big bowl and pour in the syrup mix, beating until well mixed . It will form a batter, rather than a cake mix so will be a runnier consistency.
6. Pour into the prepared tin and bake for 30-45 minutes. Check at 30 minutes to avoid overcooking. Gingerbread is nicer if it is stickier and overcooking will prevent this. It should be well risen and firm on top. 
7. Transfer the tin to a wire rack and allow the gingerbread to cool completely before cutting into squares of whatever size you desire. 
8. Gingerbread improves after a few days so I make it in advance and decorate just before serving.

To make the buttercream.
1. Beat the icing sugar and butter in a freestanding electric mixer with the paddle attachment until the mixture comes together.
2. Add the white rum to the desired strength slowly and mix until it has been incorporated. 
3. Turn up the mixer speed and beat the frosting for 3 minutes.
4. Adjust the consistency, if it is too thick by adding a teaspoon of milk at a time. The mixture requires up to 30ml of liquid and if you have only added 15ml of rum, you may need to make up the difference with milk. 
5. Now continue beating the frosting for a further 3 – 5 minutes. The longer the frosting is beaten the fluffier and lighter it becomes.
6. Pipe swirls on each piece of gingerbread and decorate with a German spiced biscuit or mini gingerbread biscuit.