Best Ever Cinnamon Buns

In a large bowl, dissolve yeast in warm water, and let stand for 3 minutes. Add cake mix, 1 cup flour, eggs, oil, and salt; beat well. Stir in remaining flour until a soft dough forms. Knead on well floured surface for about 5 minutes. Place in a greased bowl, and turn to coat the dough surface. Let rise until doubled in bulk, about 45 minutes. Preheat oven to 350 degrees F (175 degrees C). Punch down, and divide into two equal parts. Roll out each section on a lightly floured surface. Spread each with softened butter and sprinkle with sugar and cinnamon. Roll up like jelly rolls and cut buns 1 1/2 inches thick with a piece of dental floss or a dull knife. Place in greased baking pans, and allow to rise until doubled. Bake at 350 degrees F (175 degrees C) for 25 to 35 minutes or until golden brown. Meanwhile, combine confectioners sugar, 1/4 cup melted butter, vanilla, and milk. Remove baked buns from oven and drizzle with frosting.