Preparation

• Position a rack in the center of the oven, and heat the oven to 425°F.
• Cut the cauliflower into 2-inch pieces, discarding the core and green leaves. Transfer the cauliflower to a rimmed baking sheet, and toss with the oil, 1 tsp. salt, and 1/2 tsp. pepper.
• Roast the cauliflower until tender and golden in places, about 30 minutes, tossing halfway through.
• Transfer the large pieces of cauliflower to a food processor, reserving the small, dark cauliflower crumbs. Pulse, then process until smooth, scraping down the bowl as needed. Add the mascarpone and butter, and continue to process until the mixture is well combined. Season to taste with salt and pepper. Transfer to a serving bowl, and top with the reserved cauliflower crumbs and chives. Drizzle with additional oil, and serve.