Combine 1 cup flour, undissolved yeast, sugar and salt in a large mixer bowl. Heat water, butter and oil until very warm (120° to 130°F). Add to flour mixture. Beat 2 minutes at medium speed of electric mixer, scraping bowl occasionally. Add 1/2 cup flour; beat 2 minutes at high speed. Stir in enough remaining flour to make a soft dough. Knead on lightly floured surface until smooth and elastic, about 5 to 7 minutes. Cover and let rest 10 minutes.
While dough is resting, prepare caramel syrup. Combine butter, brown sugar and corn syrup in a 10-inch iron (ovenproof) skillet. Heat on stovetop or in oven until butter melts completely. Stir until smooth. Remove from heat and set aside to cool slightly.
Roll dough to a 12 x 15-inch rectangle. For filling, mix brown sugar, sugar and cinnamon in a small bowl. Spread softened butter over dough and sprinkle cinnamon sugar evenly over butter. Roll up from long side, pinching seam to seal. Cut into 12 equal slices. Arrange rolls, cut side down on top of syrup in skillet. Cover and let rise until doubled, about 45 minutes.
Bake in preheated 350°F oven for 25 to 28 minutes or until lightly browned. Cool 10 minutes on a wire rack.
Combine frosting ingredients in a small bowl, adding enough milk to reach desired consistency. Drizzle or spread frosting over warm cinnamon rolls while still in skillet. Enjoy!