Prepare Tangzhong: In a saucepan over medium heat, whisk together 24g (3 tbsp) flour and 100g (⅓ cup) whole milk. Stir until it thickens into a slurry. Remove from heat and let cool.
Make Dough: In a stand mixer, combine tangzhong, pumpkin puree, milk, dark brown sugar, yeast, egg, butter, salt, and flour. Knead for 15-20 minutes until smooth and elastic. Let dough rise in a warm place until doubled (about 1 hour).
Prepare Filling: Melt butter and set aside. Mix dark brown sugar and pumpkin pie spice.
Shape Rolls: Roll dough into a 12″ x 16″ rectangle. Spread melted butter over the dough and sprinkle the sugar-spice mixture evenly on top. Roll the dough tightly and cut into 6 equal pieces. Place in a greased 8×8 pan.
Second Rise: Cover rolls with a towel and let them rise for 30 minutes, until doubled.
Bake: Preheat oven to 350°F (175°C). Bake rolls for 20 minutes or until golden brown and an internal temperature of 180°F (82°C) is reached.
Make Frosting: Beat cream cheese, maple syrup, and salt. Add whipping cream and mix until smooth and fluffy.
Frost and Serve: Spread frosting over warm rolls and serve!