Move oven rack to lowest position. Preheat oven to 350. Pour cake mix and cocoa into clean mixing bowl; whisk together.
Add 1-1/3 cups water. Mix and bake according to package directions in 10" ungreased tube pan.
Prepare glaze when cake is cool. Place espresso granules in water in small microwave safe bowl; stir to dissolve. Mix in frosting. Microwave on HI for 20-25 seconds or until just pourable. Stir to blend.
Spread glaze over top of cake allowing some to drizzle down sides. Let glaze set and serve. Garnish with chocolate covered espresso beans if desired.