Start by preheating your oven to 350°F (175°C). Grease and line two 8-inch round cake tins. In a big mixing bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and salt. In another bowl, mix the buttermilk, oil, milk, eggs, and vanilla. Slowly pour the wet mixture into the dry, stirring until smooth. Then add in the hot water or coffee the batter will look runny, but that’s exactly how it should be.

Pour the batter evenly into your prepared pans. Bake for 30 to 35 minutes, or until a toothpick poked into the middle comes out clean. Let the cakes cool in their pans for about 10 minutes, then turn them out onto a wire rack to cool completely.

Melt the milk chocolate and butter, then stir in some cocoa powder and powdered sugar until smooth. Gently fold in the cocoa cereal (like Coco Pops) so they’re fully coated. Let the mixture sit at room temperature so it can cool and start to harden this will give it that nice crunch.

In a cold mixing bowl, whip the heavy cream with powdered sugar and vanilla until it forms stiff peaks. Set it aside while you make the frosting.

In a separate bowl, beat the softened butter until smooth and creamy. Add in the cocoa powder and mix well. Finally, fold in the whipped cream gently don’t over mix to get a light, fluffy frosting.

Put one cake layer on your serving plate. Spread some frosting on top. Place the second layer over it, then frost the top and sides of the whole cake. Use a spatula to smooth it out however you like.

Spoon the chocolate crunch mixture over the top of the cake, pressing it down slightly so it sticks. Add any extras you like chocolate shavings, sprinkles, whatever works. Pop the cake in the fridge for about 15–20 minutes so everything sets nicely before slicing and serving.