Heat oven to 350°F Grease 12-cup bundt cake pan with shortening; lightly flour.
Beat cake mix, water, bananas, butter, cinnamon and eggs in large bowl with electric mixer on low speed for 30 seconds. Increase speed to medium for 2 minutes, scraping the bowl occasionally. Stir in walnuts.
Pour into bundt pan and bake for 43-53 minutes or until toothpick comes out clean. Cool in pan for 10 minutes. Turn pan upside-down onto wire rack or heatproof serving plate and remove pan.
Cool completely. Once cool drizzle Cinnamon Glaze over cake.
Cinnamon Glaze: Stir all ingredients together until thin enough to drizzle. Sprinkle top with cinnamon for presentation.