Preheat your oven to 180°C (350°F). Bring a large pot of salted water to a boil and cook the elbow macaroni until al dente, about 8 minutes. Drain and set aside.
In the same pot, melt the butter over medium heat, listening for it to melt and bubble gently.
Add the flour to the melted butter and whisk vigorously for about 1 minute, until the mixture turns a light golden color and feels slightly thickened.
Gradually pour in the milk while whisking constantly, creating a smooth sauce. Continue whisking until the mixture thickens slightly and starts to bubble, about 3-5 minutes.
Stir in the pumpkin puree, mixing until fully incorporated and the sauce is smooth with a warm orange hue.
Add the shredded cheddar cheese and a pinch of nutmeg to the sauce, stirring until the cheese melts completely and the sauce is creamy and cheesy.
Season the sauce with salt and pepper to taste, then fold in the cooked macaroni until evenly coated with the pumpkin cheese sauce.
Transfer the mixture into a buttered baking dish, spreading it out evenly. If desired, sprinkle a little extra cheese on top for a golden crust.
Bake in the preheated oven for 20-25 minutes, until bubbling around the edges and the top is golden brown.
Remove from the oven and let rest for 5 minutes; the sauce will set slightly and the aroma of baked cheese and pumpkin will fill your kitchen.
Scoop portions onto plates, enjoy the warm, creamy, and slightly sweet pumpkin mac and cheese with a crispy top and tender pasta inside.
