Preheat your oven to 200°C (390°F). Toss the cubed pumpkin with olive oil, salt, and pepper, then spread evenly on a baking sheet lined with parchment paper. Roast for 25-30 minutes until the edges are golden and the pumpkin is tender, and your kitchen fills with a sweet, smoky aroma.
Once roasted, transfer the pumpkin cubes to a blender or use an immersion blender directly in the baking sheet. Add the minced garlic and blend until smooth and creamy, stopping to scrape down the sides if needed. The purée should be silky, with a vibrant orange color and a fragrant garlic aroma.
Pour the heavy cream into a saucepan over medium heat. Warm it gently until it starts to bubble softly, then stir in the pumpkin purée, grated Parmesan, and a pinch of nutmeg. Cook, stirring constantly, for about 5 minutes until the sauce thickens slightly and becomes velvety, with a warm, inviting hue and a fragrant blend of herbs and pumpkin.
Meanwhile, cook your pasta in a large pot of salted boiling water until al dente, following package instructions. Drain, reserving a cup of pasta water to loosen the sauce if necessary.
Add the cooked pasta to the saucepan with the pumpkin Alfredo sauce. Toss gently to coat every strand evenly. If the sauce feels too thick, stir in a splash of reserved pasta water to achieve a silky, fluid consistency that clings to the noodles.
Finish the dish by stirring in the lemon zest and chopped sage, which add a bright, aromatic contrast to the creamy, smoky sauce. Taste and adjust seasoning if needed, adding more salt or cheese for extra flavor.
Serve the pumpkin Alfredo pasta immediately, garnished with additional Parmesan and a few fresh sage leaves if desired. Enjoy the warm, velvety texture and seasonal flavors in every bite — a perfect cozy meal for fall evenings.
