Allow 3/4 cup butter and eggs to stand at room temperature for 30 minutes. Meanwhile, grease a 10-inch tube pan that does not have a removable bottom or a fluted tube pan. Add cocoa powder. Shake and tilt pan to coat bottom, sides, and tube; shake out any excess cocoa powder. In a medium bowl stir together flour, 1/3 cup malted milk powder, baking soda, and salt. Set aside.
In a small microwave-safe bowl microwave unsweetened chocolate on 100 percent power (high) for 1 to 2 minutes or until melted, stirring every 30 seconds. Cool slightly.
Preheat oven to 325 degrees F. In a large mixing bowl beat 3/4 cup butter with an electric mixer on medium to high speed for 30 seconds. Add granulated sugar and brown sugar. Beat until combined, scraping sides of bowl occasionally. Add eggs, one at a time, beating well after each addition. Beat in melted chocolate and vanilla. Alternately add flour mixture and 1 1/4 cups water to chocolate mixture, beating on low speed after each addition just until combined. Pour batter into the prepared tube pan, spreading evenly.
Bake for 55 to 60 minutes or until a wooden toothpick inserted near the center comes out clean. Cool in pan on a wire rack for 15 minutes. Remove cake from pan; cool completely on wire rack.
Meanwhile, for glaze, in a medium heavy saucepan stir together 1 tablespoon malted milk powder and 1 tablespoon water until milk powder is dissolved. Add semisweet chocolate, 1/3 cup butter, and corn syrup. Cook and stir over low heat until melted and smooth. Transfer mixture to a small bowl. Cover and chill for 30 to 40 minutes or until glaze is slightly thickened, stirring occasionally.
Drizzle glaze over cake. If desired, top with malted milk balls.