Roasting broccoli makes it sweet; topping it with Parmigiano-Reggiano cheese and broiling it makes it addictively crispy and almost nutty tasting. Slideshow: Thanksgiving Broccoli Recipes
Preheat the oven to 425°. Position a rack in the upper and lower thirds of the oven. In a food processor, pulse the butter with the garlic and cheese until smooth. Scrape the butter into a small bowl and season lightly with salt and pepper.
In a large bowl, toss the broccoli spears with the olive oil and season them with salt and pepper. Spread the broccoli spears on 2 large rimmed baking sheets and roast for 10 to 15 minutes, stirring once and shifting the pans halfway through, until the broccoli is crisp-tender and browned on the bottom.
Preheat the broiler. Return the broccoli spears to the bowl and toss with the garlic-cheese butter. Transfer the broccoli to the baking sheets, scraping all of the butter in the bowl onto the spears. Broil one pan at a time 6 inches from the heat for 2 to 3 minutes, until the butter is golden in spots. Transfer the roasted broccoli to a platter and serve.