Bring a large pot of salted water to a boil and add pasta. Cook according to the instructions on the box.
In the meantime, brown sausage in a large skillet over medium-high heat. Break into pieces with a wooden spoon.
When the sausage is done cooking, if there is a lot of fat and oil, feel free to drain.
Whisk pumpkin and mascarpone cheese into the skillet with the sausage and stir until mascarpone cheese has melted completely and the consistency is smooth.
Once pasta is done cooking, scoop it out of the pot with a slotted spoon and add to the skillet with the rest of the ingredients. Toss to coat pasta with the pumpkin, mascarpone and sausage mixture.
Using the pasta liquid, blanch the broccolini for 3-4 minutes and then, using a slotted spoon, add the drained broccolini to the skillet.
Add nutmeg, cinnamon, salt, and pepper to the skillet and toss to incorporate everything.