Preheat the oven to 425°F. Line a rimmed baking dish with parchment paper. Set aside.
Snap the cut ends off all the asparagus (as close to the end as you can) and place on the baking dish in a relatively single layer (it's okay if a few overlap).
Drizzle with the oil to generously coat the asparagus. If you need more or less than what is called for, that's ok. Sprinkle with salt and pepper. Toss with a spatula (or your hands) to evenly coat all the asparagus.
Put in the preheated oven and cook for 12-15 minutes, depending on the thickness of your asparagus. I prefer the skinny stuff, so it only takes about 12 minutes.
Remove from pan and serve immediately. Lightly drizzle with balsamic vinegar, if using.