METHOD

1. Pre-heat your oven to 150C (130C fan).  
2. Grease and line a 9-inch loaf tin with baking parchment, cutting an extra strip to line the centre of the tin lengthways and overhangs out of the tin. This will help with removing the cake from the tin. 
3. In a large mixing bowl, combine the sugar and butter and beat together until light and fluffy. Add in the eggs, one at a time and beat together until a smooth, glossy batter is achieved. 
4. Whisk together the flour, baking powder, and salt in a separate bowl. 
5. Add half of the flour mixture and mix into the batter, making sure not to over-mix. Then, pour in half of the buttermilk and mix into the batter. Finally, add the second half of the flour and mix together, followed by the remaining buttermilk, making sure not to over-mix. 

TIP – Adding these ingredients in two parts prevents a lumpy mixture. 

6. Divide the mixture into two even portions. 
7. Combine the Horlicks Original with 30ml of hot water and whisk together until smooth. Add to one of the two mixtures and mix through the batter. 
8. Next, combine the Horlicks Chocolate with 30ml of hot water and whisk together until smooth. Add to the other mixture and mix through the batter. 
9. Next, using a dessert spoon, add a heaped spoonful of the Horlicks Original mixture to the top left corner of the loaf tin, followed by a heaped spoonful of the Horlicks Chocolate mixture to the top right corner of the tin. Repeat the process, working down the tin, alternating the mixtures around so that you achieve a checkerboard effect. 

Repeat the process by adding the opposite mixture on top of the one below it (e.g. Chocolate on top of Original), until all of the batter is used up. 

10. Swirl a table knife through the batter 4-5 times to gently mingle the batters together. Do not overdo this step or you will lose definition between the layers. 
11. Transfer to the oven and bake for 1 hour and 30 minutes or until a toothpick inserted into the centre of the cake comes away clean. Leave to cool in the tin for 15 minutes before lifting the cake out of the tin and leaving it to cool entirely on a wire rack. Then slice and enjoy!