Mix cake mix, instant pudding, oil, eggs and water together with an electric mixer.
Pour half the batter into a greased and floured bundt pan.
In a small bowl, stir flour, brown sugar and cinnamon together.
Cut butter in with a fork or pastry blender to form crumbs.
Sprinkle this mixture over the batter in the pan.
Top with remaining batter.
Bake at 350 degrees for 35-45 minutes, or until a toothpick comes out clean. Cool completely.
Stir powdered sugar and milk together to make a glaze. Drizzle over cooled cake.