Preheat oven to 350 degrees F. Grease and flour a 9-inch round cake pan, set aside.

In a large bowl, whisk or sift together the flour, sugar, cocoa powder, malted milk powder, baking soda, baking powder and salt until evenly combined. Make a well in the center and add in the egg, vanilla, oil, and buttermilk. Stir until the mixture comes together and is smooth.

In a measuring cup, combine the espresso powder and hot water until the espresso powder dissolves. Slowly pour into the batter, while whisking. The batter will be thin, but that’s okay. Pour batter into the prepared pan and give it a few taps on the counter to release any air bubbles. Bake until a toothpick, inserted in the middle, comes out clean, about 25 to 30 minutes. Remove from the oven and let cool completely.

Once cooled, run a knife along the edge of the pan and invert the cake onto a cake plate or stand. Set aside.

To make the frosting, in a large bowl, cream the butter until fluffy. Add the cocoa powder, malted milk, and salt and beat until smooth. Add the sugar and vanilla and beat on low until incorporated. Increase speed to medium and add the heavy cream and beat on high until smooth and fluffy, about 3 minutes.

Pour the frosting onto the cooled cake and spread over the top with a knife or offset spatula. Top with malted milk balls if using, before cutting and serving. Leftovers can be wrapped in plastic and stored in the fridge for up to 3 days. Enjoy!