Preheat oven to 400 degrees F
Use a little vegetable oil to lightly coat the inside of a 9x13 casserole dish. Place asparagus in the dish and sparingly drizzle with the oil.
Sprinkle asparagus with Cajun Seasoning.
Roast in preheated oven until fork easily punctures thickest part of stem, about 12 minutes.
Top with Parmesan cheese and return to oven about 30 seconds.