1. Preheat the oven to 180°C (350°F). Grease a loaf tin* or line it with baking parchment. Set aside.

2. Add the butter and sugar to a large bowl and mix until light and fluffy. Add the eggs one after another and mix well after each addition. Next, add the vanilla extract and mix in. In a separate bowl mix the flour with baking powder and salt. Add the flour mix alternating with the buttermilk to the bowl and mix until just combined – do not overmix. Set aside.

3. Add the cocoa powder to a bowl and mix with the hot water until smooth. Add about 1/3 of the cake batter and mix until well combined. Next, add the cake batters with a spoon randomly into the prepared loaf tin to get an evenly mixed cake batter. Use a knife or skewer and mix a bit more to get swirls and the marble effect.

4. Place the baking tin in the oven and bake the cake for about 45-60 minutes or until a skewer inserted to the center comes out clean. Take it out of the oven and let it cool down for about 10-15 minutes in the baking tin, then remove it and let it cool down completely on a wire rack. If you like chocolate on top like me, you can brush the cake with melted chocolate – I used about 5 oz. (150g) of melted dark chocolate here.