Preheat oven to 400°.
Arrange asparagus in a single layer on a baking sheet; coat with cooking spray. Sprinkle with salt and pepper. Bake at 400° for 12 minutes or until tender.
Melt butter in a small skillet over medium heat; cook 3 minutes or until lightly browned, shaking pan occasionally. Remove from heat; stir in soy sauce and balsamic vinegar. Drizzle over asparagus, tossing well to coat. Garnish with cracked pepper and rind, if desired.