From Cooking Light Sept 2007
Coat asparagus with cooking spray and bake at 400 on a cookie sheet for 12 minutes (next time I'd try shorter, maybe 8)
Meanwhile melt 2 T butter in a small skillet until lightly browned (about 3 min). Remove from heat. Sirt in 2 t soy sauce and 1 t balsamic vinegar. Drizzle over asparagus!