Combine the starter ingredients in a saucepan and whisk constantly over medium heat until thick, about 1-2 min. Add the cooked starter & all of the dough ingredients to a bowl. Mix until combined then let rest, covered, for 20 min.
Knead the dough by hand or with a mixer & dough hook until smooth, elastic & slightly sticky. Place dough in a greased bowl, cover & let rest 1-2 hours until almost double.
Roll the dough out into 2 14”x8” rectangles. Brush the melted butter over each rectangle. Mix the brown sugar and harvest spice together then sprinkle over the butter. Top with peach slices.
Roll into logs and cut each log into 6 pieces. Place the rolls in a large buttered casserole dish. Cover & let proof for about 45 minutes. The rolls will be soft & crowding each other in the pan. Preheat the oven to 350°F. Pour some heavy cream over the proofed cinnamon rolls.
Bake for 25-30 minutes or until lightly golden & the internal temp is at least 200°F.
While the rolls are baking, make the cream cheese frosting by mixing the cream cheese, butter, vanilla, powdered sugar and salt together until smooth. Spread the frosting on warm cinnamon rolls and enjoy the ooey gooey goodness.