Preheat your oven to 180°C (350°F) and lightly grease a baking dish.
Slice the pumpkin into small cubes, about 1-inch pieces, then place them in a large pot of salted boiling water. Cook for about 10 minutes until tender and easily pierced with a fork.
Drain the pumpkin well and mash it until smooth, then set aside.
Cook the pasta in salted boiling water according to package instructions until al dente, about 8 minutes. Drain and set aside.
In a saucepan, melt the butter over medium heat. Add the flour and whisk constantly for about 2 minutes to form a roux, until it turns slightly golden and smells nutty.
Slowly pour in the milk while whisking vigorously to prevent lumps. Continue whisking until the mixture thickens, about 5 minutes, and becomes creamy.
Stir in the shredded cheddar cheese until melted and the sauce is smooth. Add a pinch of nutmeg, salt, and pepper to taste.
Fold the mashed pumpkin into the cheese sauce until fully incorporated and the sauce has a rich orange hue.
Add the cooked pasta to the sauce, tossing gently to coat all the noodles evenly.
Pour the mixture into your prepared baking dish, spreading it out evenly. Top with extra cheese if desired.
Bake uncovered for about 20 minutes, until bubbling around the edges and the top is golden brown and crispy.
Remove from the oven, let it sit for a few minutes to settle, then serve hot and enjoy the cozy, cheesy pumpkin goodness.
