Preheat oven to 400°. Arrange asparagus in a single layer on baking sheet; coat with cooking spray. Sprinkle with salt and pepper. Bake at 400° for 12 minutes or until tender.
Melt the butter in a small skillet over medium heat; cook for 3 minutes or until lightly browned, shaking pan occasionally. Make sure not to burn it just get it to a point where the butter has a nutty smell. Remove from heat; stir in soy sauce and vinegar. Drizzle over the asparagus, tossing well to coat. Serve immediately.