Rinse and dry the asparagus. Snap the tough ends off then lay the asparagus on a baking sheet. Drizzle with the olive oil, tossing slightly to coat. Grate the desired amount of parmesan cheese over the asparagus. Roast in a 350 degree F oven for 15-20 minutes, depending on the thickness of the stalks. Remove from oven and drizzle with balsamic vinegar, then return to oven for 5 minutes. Season with salt and pepper before serving.