Preheat oven to 350°.
Bring a large pot of water to a boil.
Heat milk in a small sauce pan; do not boil.
Melt butter in a separate 4 quart sauce pan. Add flour to butter and cook 3-4 minutes, stirring with a wire whisk. Add hot milk gradually, continuously stirring with a whisk to prevent lumps. Heat over medium heat until sauce thickens. Stir in the cheese. Whisk until melted. Season with salt and pepper; set aside.
Heat oil in a large skillet over medium heat. Add asparagus and sauté 4-5 minutes. Season with salt and pepper to taste. Set aside.
Cook pasta 1/2 of the recommended cook time. Drain and combine with the cheese sauce and the asparagus.
Transfer to a 13 x 9 glass baking dish, sprinkle with Parmigiano cheese. Bake uncovered for twenty minutes