Add yeast to 1/2 cup warm water. Stir and let sit for 10 minutes until it bubbles and activates.
In a bowl combine 1 cup all purpose flour, powdered milk, sugar and salt.
Add yeast mixture, oil, egg and remaining water.
Mix to combine.
Add in mashed potatoes
Add in remaining flours, one cup at a time.
Use a dough hook to knead or do by hand. Knead until dough is smooth. It will be tacky but not sticky.
Grease a large bowl and place dough in bowl, flip dough to grease both sides.
Cover with plastic wrap or cloth and allow to rise until double in size, about 1 hour.
After it has doubled, punch down and divide dough in half.
On a floured surface, roll out each piece of dough into a 12 x 8 inch rectangle.
Combine filling ingredients in a bowl and mix until it is spreadable, can warm in the microwave if needed for about 20-30 seconds to soften.
Spread each piece of dough with half of the cinnamon mixture.
Starting at wide end roll dough up tightly. Pinch the seam to seal the dough.
Using a serrated knife or a piece of thread or dental floss to cut each roll of dough into 12 pieces (1 inch each).
Place on a greased baking sheet and cover and allow to rise in a warm, draft free place until double, about 30 minutes.
Bake at 350 degrees F until lightly browned, 15-17 minutes
Remove from oven and allow to cool.
While rolls are baking make frosting.
Melt butter in a pan over low heat.
Add in brown sugar and salt. Cook on low for 2 minutes, stirring constantly.
Add milk. Remove from heat and add vanilla.
Let cool and add powdered sugar, mix until smooth.
Spread over rolls once they are cooled.
Frost with caramel frosting.