Generously butter 2 cast-iron skillets or disposable foil cake pans.
2. Step
In a large bowl, whisk together the warm milk, melted butter, and sugar. The mixture should be just warm, registering between 100-110˚F (37-43˚C). If it is hotter, allow to cool slightly.
3. Step
Sprinkle the yeast evenly over the warm milk mixture and let sit for 1 minute.
4. Step
Add 4 cups (500g) of flour to the milk mixture and mix with a wooden spoon until just combined.
5. Step
Cover the bowl with a towel or plastic wrap and set in a warm place to rise for 1 hour.
6. Step
After 1 hour, the dough should have nearly doubled in size.
7. Step
Remove the towel and add an additional ¾ cup (95g) of flour, baking powder, and salt. Stir well, then turn out onto a well-floured surface.
8. Step
Knead the dough lightly, adding additional flour as necessary, until the dough just loses its stickiness and does not stick to the surface.
9. Step
Roll the dough out into a large rectangle, about ½-inch (1 cm) thick. Fix corners to make sure they are sharp and even.
10. Step
In a medium bowl, combine softened butter, brown sugar, and pumpkin spice mix, and stir well.
11. Step
Spread the mixture onto the rolled dough.
12. Step
Roll up the dough, forming a log, and pinch the seam closed. Place seam-side down. Trim off any unevenness on either end.
13. Step
Cut the log in half, then divide each half into 7 evenly sized pieces, about 1½ inches (4 cm) thick.
14. Step
Place 7 cinnamon rolls in each skillet or cake pan, one in the center, six around the sides. Cover with plastic wrap and place in a warm place to rise for 30 minutes.
15. Step
Preheat the oven to 350˚F (180˚C).
16. Step
To prepare the frosting, in a medium mixing bowl, whisk together powdered sugar, coffee, and milk until smooth.
17. Step
Remove the plastic wrap, then bake the cinnamon rolls for 25-30 minutes, until golden brown.
