Mix the first three ingredients: shortening, salt and sugar.
Add the eggs one at a time and beat them in.
Add mashed potatoes, yeast, milk, potato water, and mix together.
Add flour: 3-4 cups, mixing well then add more flour until the dough can be handled.
Knead well on a floured surface.
Place in a large greased bowl, cover and let rise until it has doubled in size.
Lightly knead then then roll out. Add filling. Then roll and cut into cinnamon rolls.
Bake at 375 for 25-30 minutes.