In a large pot, bring salted water to a boil. Add your chosen shell or elbow pasta and cook according to package directions until al dente, usually about 8-10 minutes. Once the pasta is cooked, drain it in a colander and set it aside, allowing it to cool slightly while you prepare the creamy pumpkin cheese sauce.

In a medium saucepan over medium heat, melt 4 tablespoons of butter until foamy. Whisk in ¼ cup of flour to create a roux, stirring continuously for about 2-3 minutes, until it turns golden and smells nutty.

Gradually whisk in 2 cups of whole milk and 1 cup of heavy cream to the roux. Continue to whisk vigorously for about 5-7 minutes, until the mixture thickens and becomes smooth. Stir in 1 cup of pumpkin puree, along with a pinch of nutmeg, cinnamon, salt, and pepper.

Lower the heat and begin adding the cheeses – 1 cup of freshly grated cheddar, 1 cup of grated Gruyère, and ½ cup of grated Parmesan. Stir continuously for about 2-3 minutes, until each cheese melts completely into the sauce.

Fold the cooked pasta gently into the creamy pumpkin cheese sauce, ensuring every shell or elbow is well-coated with that luscious mixture.

In a skillet over medium heat, melt 2 tablespoons of butter until it begins to brown. Add in 1 cup of panko breadcrumbs and 2 tablespoons of chopped fresh sage. Stir for about 4-5 minutes, cooking until the breadcrumbs are golden and crispy.

Preheat your oven to 350°F (175°C). Transfer the mac and cheese mixture into a greased baking dish. Evenly sprinkle the brown butter sage breadcrumbs over the top. Bake for 25-30 minutes, until bubbling and golden brown.