1. Preheat the oven to 325°F (165°C). Grease two 6-inch round cake pans. Line the pans with parchment paper. Grease the parchment. Dust the pans with cocoa.

2. Combine the malted milk powder, flour, cocoa, baking soda, and salt in a medium bowl.

3. In a large bowl, whisk together the eggs, granulated sugar, oil, and vanilla. 

4. Add the flour mixture and milk a little at a time, beginning and ending with the flour mixture. Stir until just blended.

5. Scrape the batter into the prepared pans.

6. Bake the cakes 30 to 35 minutes, until a tester inserted in the center comes out clean.

7. Place the pans on a wire rack, and let the cakes cool 10 minutes. Remove the cakes from the pans, and return them, top side up, to the rack to cool completely.

8. Place the chocolate malt balls in a ziptop plastic bag. Seal the bag. Crush the malt balls using a meat mallet. If desired, place in a wire mesh sieve to sift out excess malt powder.

9. To prepare the frosting, combine the butter, vanilla, and malted milk powder in a mixing bowl. Beat with an electric mixer at medium-high speed until smooth. Add the melted chocolate and salt, and beat until smooth. Gradually add the confectioner’s sugar and heavy cream, beating until smooth and spreadable.

10. Place one cake layer on a cake plate or stand. Spread about one-third of the frosting on top. Sprinkle with the crushed malt balls. Place the second cake layer on top. Spread the remaining frosting on the top and sides of the cake.