I made this coffee cake for a Christmas brunch last year and it was received really well by gluten and gluten free eaters alike! The pudding really helps combat dryness which can be a problem in gluten free baking.
Mix together cake mix and pudding with whisk to blend well. Add in butter, water, and eggs and mix until well blended. Grease 9x9 pan and spread half of the cake mixture on the bottom. Mix streusel ingredients together until moist. Spread 2/3 cup of mixture over the top of cake batter. Repeat layer once more. Bake per cake box's directions. When cooled combine glaze ingredients and drizzle over the top.