Baked macaroni and cheese with asparagus

This is a simple application of a basic cheese sauce. I don't think it's based on any recipe in particular, although it's probably inspired by the macaroni-and-cheese cookbook that I picked up a year or two ago.

1 lb pasta, cooked 1–2 minutes short
2 cups hot milk
8 oz good cheese, shredded
1 nutmeg
1 oz + 1 tsp butter
1 oz flour
bunch asparagus
1 leek, cleaned and chopped

To prepare asparagus: Heat oven to 400°F. Season asparagus and toss in vegetable oil. Roast asparagus on a wire rack over a sheet pan for 8–10 minutes, until tender. Chop roasted asparagus in 3/4-inch pieces. Reduce oven to 375°F.

To make cheese sauce: Melt 1 oz butter in saucepan. Cook chopped leek, covered, stirring regularly, until soft and transparent. Add 1 tsp butter and then 1 oz flour. Stir until a roux is formed and let cook over medium heat for 1–2 minutes. Add hot milk, whisking rapidly, until fully incorporated. Simmer until thickened, then add cheese and 1/8 tsp freshly grated nutmeg. Stir until completely mixed, then stir in chopped asparagus.

Put cooked pasta into a 9×13 casserole and mix sauce into pasta. Bake for 20 minutes.