Prep for Roasting: Preheat your oven to 425°F / 220°C.
Line a large baking sheet with parchment paper.
Season the Asparagus: Trim the tough, woody ends off the asparagus spears. On the baking sheet, toss the spears with olive oil and a sprinkle of salt until they are evenly coated.
Arrange them in a single layer.
Roast and Top with Cheese: Bake for 10-15 minutes, or until the asparagus is tender-crisp. Carefully remove the pan from the oven and sprinkle the Parmesan cheese evenly over the top.
Melt and Crisp: Return the pan to the oven for another 3-5 minutes, just until the cheese is melted, bubbly, and beginning to turn golden brown.
Serve immediately for the best crispy texture.
Don't overcrowd the pan! Give the asparagus spears space to roast in a single layer, otherwise they will steam and become soft instead of crispy.