Preheat oven to 350 degrees F. Line 2 muffin tins with about 18-20 paper liners; set aside.
In a large bowl, combine the cake mix, buttermilk, oil, eggs, malt powder, and chocolate pudding powder with an electric mixer until combined and smooth, 2 minutes. Portion the batter evenly among the muffin tins, filling about 3/4 full. Bake for 16-18 minutes or until a toothpick inserted near the center comes out clean. Cool completely.
In the bowl of a stand mixer, cream together the softened butter, vanilla, malted milk powder, and cocoa powder until smooth, 1 minute. Gradually add in the powdered sugar, beating well after each addition and alternating with the heavy whipping cream if frosting gets too thick and paste-like. Frosting is finished when it is light and fluffy.
Pipe or spread the frosting onto the cooled cupcakes. Immediately garnish with sprinkles and malted Easter eggs or malt ball candies.