Preheat the oven to 400ºF (205ºC). Position an oven rack to the center position.
Rinse the asparagus and pat dry with a cloth.
Snap off the ends of the asparagus. Hold onto the bottom of the spear with your hands and lightly bend the spear. If the spear is very bendy and won’t snap at that point, move up the spear by about a 1/2 inch and try snapping again. Asparagus naturally snaps at the point when it starts to get tough and they can vary between each spear. (You can also trim the bottoms by slicing them off.)
Transfer the asparagus to a large sheet pan.
Drizzle the olive oil over the asparagus. Rub and roll the spears over the baking sheet so that they are covered with oil. Add a small splash of oil if there wasn’t enough to coat the asparagus. Spread the spears over the sheet pan into a single layer, making sure they’re not tightly packed together.
Sprinkle the salt and pepper over the asparagus. Transfer the sheet pan into the oven. For pencil thin spears (about 1/4-inch thick), roast them for 7 to 8 minutes. Medium-thick spears (1/2 inch thick) will take about 8 to 9 minutes. Thicker ones (closer to 3/4-inch thick or more) will take about 11 to 13 minutes of roasting.
Take the asparagus out of the oven and sprinkle the lemon zest on top. Use a spatula to gently toss the asparagus with the lemon zest. Serve immediately.