Cook the pasta. Bring a large pot of generously salted water to a boil. Cook the pasta according to package directions until al dente. Before draining, reserve at least 1 cup of pasta water.
Brown the sausage. While the pasta cooks, heat a large skillet or Dutch oven over medium-high heat. Add the sausage, breaking it into small pieces as it cooks. Cook for 6–8 minutes, stirring occasionally, until deeply browned and cooked through. Transfer the sausage to a plate, leaving the flavorful browned bits in the pan.
Brown the sage. Reduce the heat to medium and add the butter to the skillet. Add 5–6 whole sage leaves and cook for 1–2 minutes, until fragrant and lightly crisp. Remove the sage and set aside for serving.
Build the flavor. Add the diced shallot to the sage-infused butter and sausage drippings. Cook for 2–3 minutes, until softened. Add the garlic and remaining chopped sage and cook for about 30 seconds, until fragrant.
Make the pumpkin sauce. Stir in the pumpkin purée, chicken broth, heavy cream, nutmeg, salt, and several generous grinds of black pepper. Bring to a gentle simmer and cook for 3–4 minutes.
Add the kale and sausage. Stir in the finely chopped dino kale and browned sausage. Simmer for 2–4 minutes, until the kale is tender and the sausage is warmed through. If the sauce becomes too thick, add 1/2c of reserved pasta water.
Add Parmesan and acidity. Reduce the heat to low and stir in the Parmesan. Add 1 teaspoon of apple cider vinegar and taste. Add another teaspoon if needed. The acidity should brighten the sauce and balance the richness without making the dish taste vinegary.
Toss with pasta. Add the cooked pasta directly to the sauce and toss well. Gradually add reserved pasta water, a little at a time, until the sauce is silky and coats the noodles beautifully.
Finish and serve. Taste and adjust the salt and pepper as needed. Serve topped with more freshly grated Parmesan, toasted pepitas, and reserved crispy sage leaves.
