In a large skillet, melt butter over medium high heat. Add asparagus and stir well. Cook and stir asparagus over medium high heat until crisp-tender. Thin asparagus will cook in about 7 to 8 minutes, while thicker asparagus may take up to 15 minutes.
Bite into a piece to check doneness after asparagus turns bright green and looks tender. If it is not tender enough, cook another minute or two. Salt and pepper to taste, and serve immediately.