Preheat oven to 350°. Spray a 15-cup Bundt pan with baking spray with flour.

In a medium bowl, whisk together chocolate, cocoa, and coffee until chocolate is melted.

In a large bowl, beat butter, sugar, and vanilla with a mixer at high speed until fluffy, 3 to

4 minutes. Add egg whites, one at a time, beating well after each addition. With mixer on low speed, add chocolate mixture; beat until combined.

In a medium bowl, whisk together flour, baking powder, salt, and baking soda. Gradually add flour mixture to butter mixture alternately with buttermilk, beginning and ending with flour mixture, beating just until combined after each addition. Pour batter into prepared pan.

Bake until a wooden pick inserted near center comes out clean, about 47 minutes. Let cool in pan for 10 minutes. Invert onto a wire rack, and let cool completely. Drizzle Butterscotch Glaze over cake.