Fire up your grill to high heat, aiming for 450-500°F on the grate surface. Clean and oil the grates well to prevent sticking. While the grill heats up, snap off the tough woody ends of the asparagus spears - they will break naturally at the right spot when bent gently.

In a large bowl, toss the trimmed asparagus with olive oil, kosher salt, black pepper, and garlic powder if using. Make sure every spear gets coated evenly - this oil coating is crucial for preventing sticking and achieving those beautiful char marks.

Place asparagus spears perpendicular to the grill grates to prevent them from falling through. Grill for 4-6 minutes on the first side without moving them - you want to see good char marks developing before flipping.

Using long tongs, carefully roll each spear a quarter turn and continue grilling for another 4-6 minutes. The asparagus is done when you can pierce the thick end easily with a knife but it still has some firmness. Look for bright green color with beautiful char marks.

Transfer the grilled asparagus immediately to a serving platter. While still hot, sprinkle generously with fresh grated Parmesan cheese and drizzle with lemon juice. The cheese will slightly melt from the residual heat, creating the perfect finish.