In a small bowl, combine the warm water and yeast. Set aside.
In a large bowl, whisk together 4 cups of the flour and cake mix. Then, pour in the water/yeast mixture and mix until well combined. Continue to add flour until a soft dough has formed, you may not use all of the flour.
Place the dough into a bowl, cover and let the dough rise until it has double. The rising process will take 30 minutes to an hour.
Punch the dough down and roll it out onto a floured surface. The dough needs to be about 1/2 inch thick and close to a rectangular shape as possible.
Brush the melted butter all over the top of the rolled out dough. In a small bowl, combine the brown sugar and cinnamon and then sprinkle it all over the butter.
Roll the dough up from the long side. Slice the dough into 12 1-inch thick rolls. The ends will make a few extra smaller rolls, you can discard these or squeeze them into your pan. Place all of the rolls into a greased 9 x 13 pan and cover with plastic wrap. Let the rolls rise until they have almost doubled, about 15-20 minutes.
Bake at 375 degrees for 8-10 minutes.
For the frosting, place all of the ingredients into a medium sized bowl and mix until well combined. Frost over the cinnamon rolls while warm, the frosting will be thick.
These are best served while warm.