Grilled Brussels Sprouts

From Food52
Ingredients:
24 brussels sprouts
3 Tbsp. olive oil
1 tsp. salt
1 tsp. cracked black pepper
1 3/4 tsp. onion powder
1 3/4 tsp. garlic powder
1 tsp. celery salt
Zest of 1 lemon (optional)
1 Tbsp. shredded parmesan (optional)

First, clean the sprouts. Trim the cut ends back without interferring with the leaves, and peel any withered leaves off the bulb. Score the bottoms; one cut will suffice.
Then place the sprouts in boiling, salted water for no more than five minutes. NO MORE!
Drain, drizzle with oil and toss in a bowl with the salt, pepper, onion powder, garlic powder and celery salt.
When the sprouts are nice and coated, place on a hot grill (but keep the bowl handy), turning every four minutes for a total of twelve minutes.
Remove from the grill back to the seasoning bowl and toss to coat with any remaining seasoning.
If desired, add lemon zest and parmesan cheese.