In a large mixing bowl, add eggs, water, oil and mix until smooth.
Add cake mix and flour and mix until just combined.
Spread batter in a greased and floured cake pan (Dimensions: 9x13 rectangle pan or two 8x8 pans).
Make topping by adding reserved cake mix, flour, brown sugar, butter, cinnamon powder in another mixing bowl,
Mix with a fork until crumbly.
Sprinkle this topping on top of the cake batter.
Bake at 350 degrees F for about 30 minutes or until a toothpick inserted in the center comes out mostly clean with a few crumbs.
Allow cake to cool to room temperature.
While cake is cooling, prepare glaze by mixing together powdered sugar and water in a small mixing bowl until thick and smooth.
Drizzle this on top of the cake. You don't have to use all of it. Enjoy!