Preheat oven to 450 degrees. Trim 1 inch from stems of broccoli. Using a vegetable peeler, peel outer layer of stems; cut diagonally into 1/2-inch slices. Separate florets into bite-size pieces.
In a large bowl, toss florets and stems with olive oil, salt, and pepper.
Spread in a single layer on a rimmed baking sheet; roast, turning broccoli halfway through, until tender, about 15 minutes.