Snap ends off of stalk end without tender leaves. Rinse, drain and pat asparagus dry. Put into dish you can cover with lid. Drizzle oil and balsamic over vegetables, add garlic and salt and pepper. Cover and shake to insure all of the stalks are covered with the marinade and let sit for 15 minutes.
Preheat grill on high for 5 minutes and grill stalks for 4-6 minutes; flipping once. I typically use young thin stalks so 4 minutes is plenty but if you get thicker ones, adjust cooking time accordingly. They should be crunchy and bright green; do not cook until they turn a dull green; they're overdone at that point.
Put on serving plate and garnish with Parmesan cheese. (I grated some from a block but have used pre-shredded too).