01 - Preheat oven to 400°F (200°C). Lightly grease a 9x13-inch baking dish.
02 - Bring a large pot of salted water to a boil. Add ziti and cook until just al dente, about 2 minutes less than package directions. Drain and set aside.
03 - Heat olive oil in a large skillet over medium heat. Add chopped onion and sauté until soft and translucent, approximately 5 minutes. Stir in minced garlic and cook for 1 minute more.
04 - Add pumpkin purée, vegetable broth, and heavy cream to the skillet. Stir until smooth and bring to a simmer.
05 - Mix in Parmesan, nutmeg, sage, and chili flakes if desired. Season with salt and freshly ground black pepper. Simmer for 3–4 minutes, adjusting seasoning to taste. Remove from heat.
06 - In a large bowl, toss the cooked ziti with the pumpkin sauce and half of the shredded mozzarella cheese.
07 - Spoon half of the pasta mixture into the prepared baking dish. Tear one burrata ball over the pasta and scatter half of the remaining mozzarella on top.
08 - Layer the rest of the pasta mixture over, tear the second burrata ball on top, and finish with the remaining mozzarella and all the grated Parmesan.
09 - Bake uncovered for 25–30 minutes, or until golden brown and bubbling. Remove from oven and let rest for 5 minutes.
10 - Garnish with chopped fresh basil before serving.