Steaming asparagus plays up its delicate grassy flavor.
Set a steamer basket in a saucepan with 2 inches simmering water. Add asparagus, cover, and steam until crisp-tender, about 6 minutes. Transfer to a platter.
Discard water and wipe pan dry. Heat butter over medium, swirling pan occasionally, until golden brown and most of the foam has subsided, 5 to 6 minutes. Pour over asparagus and toss to combine. Season with salt and pepper. Sprinkle with hazelnuts, and serve immediately.