In this recipe, cauliflower's mild but distinct flavor is enhanced with a sauce comprising brown butter and roasted hazelnuts. Be sure to monitor the butter carefully: You'll want it to brown, but not burn.
Preheat oven to 350 degrees. Place hazelnuts on a baking sheet; toast until fragrant, about 10 minutes. Transfer nuts to a kitchen towel; rub off loosened papery skins. Coarsely chop nuts; set aside.
Trim stems of cauliflower so they sit flat, keeping head intact. Bring several inches of water to a boil in a large steamer or in a pot fitted with a rack; add salt to taste. Steam cauliflower until just tender, about 10 minutes. Transfer to a platter.
In a medium saucepan, melt butter over medium heat. Add hazelnuts, and cook until butter turns brown, 3 to 4 minutes. Remove from heat, and add lemon juice and chives. Season with salt, and stir to combine. Pour over cauliflower, and serve immediately.