Preheat oven to 425F. Move the rack to the middle position and line a baking sheet with parchment paper.
Grate your parmesan (and mozzarella if you didn't buy a pre-shredded one). Trim the asparagus ends.
Place the asparagus on the baking sheet. Add the garlic powder, salt & pepper, and olive oil. Toss until coated. Arrange the asparagus in a mostly single layer (you want the asparagus spears to touch/overlap slightly).
Sprinkle the mozzarella over the asparagus. I tend to concentrate it around the middle like in the photos. Sprinkle the parmesan over top of the mozza.
Roast the asparagus for 12-15 minutes or until it's cooked through and the cheese is nice and melty. Optional: broil for a couple of minutes to brown the cheese up (watch it carefully). Serve immediately.
I used thin asparagus because it cooks faster. You will have to adjust cooking time if you buy thicker asparagus (or buy thicker if you prefer it to be more crisp).