Step 1

Preheat your oven to 350°F/175°C. Butter or grease two 8-inch cake pans and line it with parchment paper.

Step 2

Combine the flour, cocoa powder, sugar, baking powder, baking soda, and salt in a large bowl with a whisk.

Step 3

In a large jug, whisk together the buttermilk, oil, eggs, and vanilla extract.

Step 4

Slowly pour in the ingredients from the large jug and mix until just combined.

Step 5

Slowly add the hot water and mix. Your batter will be very thin and it makes a lot of cake batter!

Step 6

Pour the batter into the prepared pans. Bake for 35-40 minutes, until a toothpick comes out clean when inserted

Step 7

Allow the cakes to cool for 10 minutes before removing from the pans. Let them cool completely on a cooling rack.

Step 8

In a stand mixer fitted with the paddle attachment, beat the butter and confectioners' sugar together on low speed until well combined.

Step 9

Increase the speed to medium-high and beat for 2 minutes until it becomes very thick.

Step 10

Stop the mixer and add the salt and vanilla extract into the bowl. Beat on medium-high speed for another 2 minutes.

Step 11

Turn the mixer to your lowest speed and pour in the heavy cream. Beat until it becomes very creamy and spreadable.

Step 12

Assemble your cake and enjoy!