Preheat oven to 425°F. Place asparagus on a large rimmed baking sheet; drizzle evenly with olive oil, and sprinkle with salt and pepper. Toss to coat. Roast in preheated oven until asparagus are crisp-tender, about 12 minutes.
While asparagus roasts, melt butter in a small skillet over medium. Cook, whisking often (this cuts down on sputtering), until deeply fragrant with a toasty aroma and darkened to the color of light brown sugar, 3 to 4 minutes. Pour butter into a small bowl, and let cool slightly, about 2 minutes. Whisk in oyster sauce.
Arrange asparagus on a platter, and drizzle evenly with oyster-butter sauce. Serve hot.
