Step 1

Preheat oven to 350°F/175°C. Grease 3 8-inch cake pans with butter, then line the bottoms with parchment paper.

Step 2

Combine the flour, cocoa powder, sugar, baking powder, baking soda, and salt in the bowl of a stand mixer, using the paddle attachment. Set aside. In a large jug, combine the buttermilk, oil, eggs and vanilla.

Step 3

While the mixer is on low speed, slowly pour in the wet ingredients. While mixer is till running, slowly add the boiling water and mix. Your batter will be very thin.

Step 4

Pour the batter into the prepared pans (about 22 ounces/600 grams per pan). Bake for 35-40 minutes, until a toothpick comes out clean when inserted.

Step 5

Allow the cakes to cool completely

Step 6

In a stand mixer with the whisk attachment, add butter and sugars, beat until fluffy and pale, about 2-3 minutes. Add the vanilla and mix again.

Step 7

Reduce the speed and slowly add in the flour, nutmeg and salt. Mix until just combined. Add in the milk/heavy cream a tablespoon at a time until you have your desired consistency. Fold in your chocolate chips.

Step 8

Divide the dough in two and shape into 8 inch circles. Wrap in clingfilm and keep in the fridge until ready to use.

Step 9

In a stand mixer with the whisk attachment, beat the butter, powdered sugar, cocoa powder and salt together. Start on low and then increase the speed to stop the dry ingredients from flying out. Beat until fluffy, it will start off looking sandy but will come together. Pour in the melted chocolate, heavy cream and vanilla and beat for another minute.

Step 10

If the frosting isn't as spreadable as you would like, add more heavy cream a tablespoon at a time.