Preheat your oven to 180°C (350°F) and set a baking dish aside.
Cook the pasta in salted boiling water until al dente, about 8 minutes, then drain and set aside.
In a saucepan, melt butter over medium heat and whisk in flour, stirring constantly for about 1 minute until it forms a smooth paste.
Gradually pour in the milk, whisking continuously, and simmer for about 5 minutes until the sauce thickens slightly and becomes silky.
Stir in the shredded cheddar cheese until melted and smooth, then fold in the roasted pumpkin puree.
Season the mixture with salt, pepper, and a pinch of nutmeg for warmth and depth.
Combine the cooked pasta with the cheese and pumpkin sauce, stirring gently to coat all the noodles evenly.
Transfer the coated pasta into the prepared baking dish, spreading it out evenly.
Sprinkle the bread crumbs over the top for a crispy finish, and add a little extra cheese if desired.
Bake in the preheated oven for 20-25 minutes until bubbling around the edges and golden on top.
Remove from the oven, let rest for a few minutes, then serve hot, enjoying the creamy, cheesy pumpkin flavor.