Preheat your oven to 350°F.
Cook your macaroni al dente according to the instructions on the packaging.
16 ounces macaroni
To a large pot over medium heat, add the butter and flour. Form a roux by heating and whisking until the butter is melted and it is combined with the flour.
2 tablespoons unsalted butter, 2 tablespoons all-purpose flour
Add the milk and whisk to combine.
1 cup milk
Set aside about ½ cup of cheese for the top and add the rest along with the pumpkin puree, garlic powder, nutmeg, and black pepper. Continue to heat and stir until cheese is completely melted and you have a thick sauce.
15 ounces pumpkin puree, 16 ounces cheddar cheese, ½ teaspoon garlic powder, ¼ teaspoon nutmeg, ¼ teaspoon black pepper
Add the cooked macaroni to the cheese sauce and stir to coat. Transfer to a 9x13-inch oval or rectangular casserole dish and top with the cheese you set aside.
Bake for 10 minutes, then turn your oven up to broil. Watch closely and remove when the top starts to brown.
Garnish with fresh sage (optional) and serve hot.
¼ ounce fresh sage