There is no comparing this to a Bundt cake made with a mix. Only a from-scratch cake could be this moist and rich. This mocha glaze is an indulgence; you can also sprinkle the cake with confectioners' sugar, if you like. This one is from Good Housekeeping.
Preheat oven to 350 degrees. Grease 12-cup Bundt pan. On sheet of waxed paper, stir together flour, baking soda, baking powder, and salt. In 2-cup measuring cup, mix cocoa, espresso-coffee powder, and hot water until blended; set aside. In large bowl, with mixer at low speed, beat sugar, oil, egg whites, and whole egg until blended.
Increase speed to high; beat until creamy, about 2 minutes. Reduce speed to low; beat in cocoa mixture, chocolate, and vanilla. Add flour mixture alternately with buttermilk, beginning and ending with flour mixture. Beat just until combined, scraping bowl occasionally with rubber spatula.
Pour batter into prepared plan. Bake 45 minutes, or until toothpick inserted in center of cake comes out clean. Cool in pan on wire rack 10 minutes. With small knife, loosen cake from side of pan; invert onto wire rack. Cool completely. Meanwhile, prepare Mocha Glaze. Place cake on cake plate; pour glaze over top of cooled cake, letting it run down sides. Allow glaze to set before serving.
Mocha Glaze: In medium bowl, combine 1/4 teaspoon instant espresso-coffee powder and 2 tablespoons hot water; stir until dissolved. Stir in 3 tablespoons unsweetened cocoa, 3 tablespoons dark corn syrup, and 1 tablespoon coffee-flavored liqueur until blended. Stir in 1 cup confectioners' sugar until smooth. Makes about 1 cup.