1. Heat oven to 350 degrees F. Coat 9- to 12-cup decorative bundt pan with nonstick cooking spray.
2. In bowl, mix chips and water until chips are moistened. Add 1-1/2 teaspoons cake flour; toss to coat.
3. In second bowl, lightly stir together egg whites, 1/4 cup of the buttermilk and the vanilla.
4. In clean large bowl, beat 3 cups sifted flour, sugar, baking powder, baking soda and salt 30 seconds. Add butter and remaining 3/4 cup buttermilk; beat on low speed until evenly moistened. Increase speed to medium; beat 1-1/2 minutes. Add egg mixture in 3 batches, beating 20 seconds after each addition. Stir in coated chocolate chips. Scrape batter into prepared pan; smooth surface.
5. Bake in 350 degrees F oven until cake tester inserted in center comes out clean and top springs back when lightly pressed, about 55 minutes.
6. Remove pan with cake to rack; let cake cool in pan 10 minutes. Unmold onto rack; let cool.Glaze:
7. Place chocolate in small bowl. In small saucepan, heat cream to boiling. Pour over chocolate; let stand 2 minutes. Gently stir until smooth; let cool slightly, 15 minutes. Pour over top of cooled cake, letting it dribble down sides. Do not spread to avoid marks in glaze. Let cake stand for glaze to set, about 1 hour.