In a large mixing bowl, combine 2 cups of flour, sugar, yeast, and salt. Add warm milk, pumpkin puree, melted butter, and the egg. Mix until smooth. Gradually add the remaining flour, 1/2 cup at a time, until a soft dough forms. Knead the dough on a floured surface for about 5 minutes, or use a dough hook with a stand mixer for 3 minutes, until the dough is smooth and elastic.
Place the dough in a greased bowl, cover it with a clean towel, and let it rise in a warm place for about 1 hour, or until it has doubled in size.
While the dough is rising, mix the softened butter, brown sugar, cinnamon, and optional spices in a small bowl until well combined.
Once the dough has risen, punch it down and roll it out on a floured surface into a large rectangle, about 1/4 inch thick.
Spread the cinnamon-sugar mixture evenly over the rolled-out dough, leaving a small border around the edges.
Starting from the long side, tightly roll up the dough into a log. Cut the log into 12 equal slices and place them in a greased or parchment-lined 9x13 inch baking dish.
Cover the dish with a towel and let the rolls rise for another 30 minutes.
Preheat the oven to 350°F (175°C). Bake the rolls for 20-25 minutes, or until they are golden brown and cooked through.
While the rolls are baking, whisk together the powdered sugar, milk or cream, and vanilla extract until smooth.
Once the rolls are done, drizzle the glaze over them while they are still warm. Serve and enjoy!