The perfect roasted asparagus should be lightly browned and tender, yet bright green and crisp. Roasting the spears at a high temperature helps achieve this. We also browned grated Parmesan to make a nutty, crumbly frico topping. Wait until ready to serve to top the vegetables so the crisped cheese stays crunchy.
Preheat the oven to 450 degrees F. Line a baking sheet with a wire rack.
Put the asparagus, olive oil, 1/2 teaspoon kosher salt and 1/4 teaspoon pepper in a medium bowl. Toss to coat evenly. Spread the asparagus in a single layer on the prepared baking sheet. Roast for 10 to 12 minutes, until lightly browned and tender, but still bright green.
Meanwhile, spread the Parmesan evenly in the bottom of a medium nonstick skillet over medium heat. Cook undisturbed until the cheese melts, sticks together and turns golden brown, about 2 minutes, then flip with a rubber spatula and cook until golden on the second side, about 2 minutes more. Transfer the frico to a wire rack-lined baking sheet to cool completely, about 2 minutes. Break the frico into small crumbles and put in a small bowl. Add the lemon zest and 1/2 teaspoon black pepper and toss to combine.
Transfer the roasted asparagus to a serving platter and squeeze the fresh lemon juice over the top. Top with the crumbled frico mixture.