Preheat your oven to 180°C (350°F) and butter a baking dish to prevent sticking.
Cook the elbow macaroni in salted boiling water until just al dente, about 8 minutes. Drain and set aside.
Melt the butter in a large saucepan over medium heat, listening for a gentle sizzling as it melts.
Add the flour to the melted butter and whisk constantly for about 1 minute until the mixture smells lightly nutty and turns a pale golden.
Gradually pour in the milk while whisking continuously to create a smooth, creamy sauce. Bring to a simmer and cook for about 5 minutes until thickened and silky.
Stir in the shredded cheddar, grated Parmesan, and pumpkin puree. Mix until the cheese melts completely and the sauce turns a vibrant orange with a velvety texture.
Season the sauce with salt, pepper, and a pinch of cayenne to taste, stirring to combine.
Combine the cooked pasta with the cheese sauce, folding gently to coat every piece evenly.
Pour the coated pasta into your prepared baking dish, spreading it out evenly.
Top with a little extra cheese if desired, then bake for about 20 minutes until bubbling around the edges and golden on top.
Remove from the oven and let rest for 5 minutes to allow the cheese to set slightly and the dish to cool just enough for serving.
Scoop onto plates, enjoy the warm, cheesy, pumpkin-infused goodness, and savor the cozy flavors!