In a large nonstick or well-seasoned cast-iron skillet, heat the oil over medium-high heat. Add the gnocchi and cook, stirring occasionally, until lightly browned, 5 to 7 minutes.
Meanwhile, in a small bowl, mash the butter, miso, and vinegar until combined.
Add the asparagus and a pinch of salt. Cook, tossing occasionally, until the asparagus are bright green and crisp-tender, 3 to 4 minutes. Remove from heat and stir in the miso butter until melted and combined. Serve right away.
