From America's Test Kitchen Season 10: Great Glazed Chicken
Roasting can concentrate flavor to turn dull vegetables into something great, but roasting broccoli usually makes for spotty browning and charred, bitter florets. We wanted to figure out how to roast broccoli so that it turned out perfectly browned and deeply flavorful every time. To ensure that the broccoli would brown evenly, we cut the crown into uniform wedges that lay flat on the baking sheet, increasing contact with the pan. To promote even cooking of the stem, we sliced away the exterior and cut the stalk into rectangular pieces slightly smaller than the more delicate wedges. After trial and error, we discovered that preheating the baking sheet helped the broccoli cook faster, crisping but not charring the florets, while a very hot oven delivered the best browning. Sprinkling a little sugar over the broccoli along with the salt and pepper helped it brown even more deeply. We finally had roasted broccoli with crispy-tipped florets and sweet, browned stems.
Trim away the outer peel from the broccoli stalk, otherwise it will turn tough when cooked. For Roasted Broccoli with Garlic, stir 1 tablespoon minced garlic into the olive oil before drizzling it over the broccoli.