Bloom the yeast: Warm the milk to 105–115°F (40–46°C). In a small bowl, combine warm milk with 1 teaspoon of the sugar. Sprinkle the yeast over the top and let sit until foamy, 5–10 minutes.
Make the dough: In the bowl of a stand mixer, whisk together the remaining sugar, pumpkin puree, melted butter, egg, vanilla, salt, and pumpkin pie spice. Add the bloomed yeast mixture and mix to combine.
Add flour: With the dough hook on low, add the flour in 2–3 additions until a soft, slightly tacky dough forms. Increase to medium and knead until smooth and elastic, 6–8 minutes (or knead by hand 8–10 minutes).
First rise: Place dough in a lightly greased bowl, cover, and let rise in a warm spot until doubled, about 60–90 minutes depending on room temperature.
Prepare filling: In a small bowl, combine brown sugar, cinnamon, pumpkin pie spice, and salt. Set out the softened butter for spreading.
Roll out: Punch down the dough and turn onto a lightly floured surface. Roll into a 12×18-inch (30×46 cm) rectangle with the long side facing you.
Fill and roll: Spread the softened butter evenly over the dough. Sprinkle the sugar–spice mixture over the butter and gently press to adhere. Add pecans, if using. Tightly roll up from the long edge to form a log; pinch the seam to seal.
Cut: Trim the ends if needed, then slice into 12 even rolls using a sharp knife or floss. Arrange cut-side up in a greased 9×13-inch pan, leaving slight space between rolls.
Second rise: Cover and let rise until puffy, 30–45 minutes. Meanwhile, preheat the oven to 350°F (175°C).
Bake: Bake for 22–27 minutes, until the centers are just set and the tops are lightly golden. Avoid overbaking to keep the rolls soft and gooey.
Frosting: Beat cream cheese and butter until smooth. Mix in powdered sugar, vanilla, a pinch of salt, and enough milk/cream to reach a spreadable glaze.
Finish and serve: Spread frosting over warm rolls so it melts into the swirls. Serve warm and enjoy!