Wash asparagus and snap off the bottom of the stalks
Place damp asparagus onto a piece of heavy duty foil - shiny side up - large enough to leave 2-3 inches of clear foil on either side and 4-5 inches top and bottom of the asparagus
drizzle olive oil over asparagus and toss to coat
sprinkle with Parmesan, lemon zest (or juice), pepper, and salt, toss to coat
Bring the top and bottom edges of the foil together and fold over several times, leaving some air space between vegetables and foil.
Repeat with each side of your foil package until a sealed pouch is formed
Cook pouch indirectly on the BBQ - meaning on an upper rack, over a non-burning element, or to the side of your burning charcoal - for about 14 mins, flip the pouch over after 7 mins. Total cooking time will vary with heat level of BBQ/fire mins
When vegetables are cooked, the pouch will swell up with steam. Note - this will only work if your pouch is well sealed and you haven't accidentally poked a hole in it during handling.
Open foil pouch and serve. Watch out for the steam when you first tear the foil - especially if the pouch is puffed up!