Rinse spears under cold water and pat completely dry — dry spears char better. Snap or cut off the woody bottom inch. Thicker spears handle high heat best; thin ones cook fast and go limp quickly, so watch them. Toss on a baking sheet with olive oil, kosher salt, and black pepper. Optional: marinate 30–60 minutes with balsamic vinegar and minced garlic for extra depth.

Set up the grill for high heat. Charcoal: light a full chimney, let coals ash over, spread across half the grate, preheat 5 minutes, then clean and oil grates. Gas: preheat at least half the burners to high. You need intense heat for char before the spears go limp. Lay oiled, seasoned spears perpendicular to the grill bars. Use a grill basket if spears are thin. Don't crowd — steam kills char. Grill, turning every couple of minutes with tongs: thin spears 3–5 min, medium 5–8 min, thick finger-width 8–10 min. Cook until well-charred outside and tender throughout. Don't walk away — they overcook fast. Optional: grill lemon halves cut-side down alongside the asparagus, about 3 minutes, until charred. Squeeze over spears to finish.

Done when spears show char marks, feel tender with a fork, and droop slightly but still have a little bite. Exterior looks slightly shriveled; interior stays juicy. Soft all the way through with no resistance means one minute too long. Transfer immediately to a platter. Season with salt, pepper, and a drizzle of olive oil. Add a squeeze of lemon if desired. Serve right away — asparagus doesn't hold well. Key mistakes: grill not hot enough (spears steam instead of char), leaving thin spears on past the 3-minute mark, and overcrowding the grate (grill in batches if needed).