Preheat a grill to medium high heat or an oven to 425 degrees F.
Coat 4 large squares of foil with cooking spray.
Divide the asparagus stalks evenly among the squares of foil.
Sprinkle the Italian seasoning, salt and pepper evenly over the asparagus stalks.
Place 2 teaspoons of butter in each asparagus packet.
Fold the foil over the asparagus, sealing completely on all sides.
Grill the asparagus packs for 15 minutes, flipping once halfway through.
Alternatively, you can bake the asparagus for 15 minutes.
Open the foil packets carefully, then gently stir to make sure all the asparagus is coated with the butter and seasonings.
Sprinkle with parsley and serve, with lemon wedges if desired.