1.Combine yeast and 1/2 c of warm water,set aside for 10 mins or until bubbly.
2.In a large mixing bowl,combine butter,sugar,milk,salt,mashed potatoes,hot water until the butter melts,add eggs and yeast mixture,mix well.
3.Add 2 cups of all purpose flour,continue adding flour(1 cup at a time),until soft dough forms,pour flour on a flat surface and knead the dough until becomes elastic and smooth.
4.Place in a greased bowl and cover,let rise for atleast 1 hours.
5.Meanwhile,combine sugar and ground cinnamon for filling.
6.Get and punch dough down to remove air inside of it,then divide in half,roll on a floured surface,flatten it using rolling pin and spread with half of the butter(for filling).
7.Sprinkle half of the cinnamon mixture over surface,roll up tightly lengthwise then seal the edges by pinching it.cut into 12 slices then place in a greased pan.repeat the procedure to the remaining dough.
8.Cover and let it rise for 40 mins or until double it size.
9.Bake in 350 degrees f oven for 25 mins.cool for 15 minutes.
10.Prepare the icing by combining all the ingredients and drizzle over the rolls,serve warm and enjoy eating!