Put a baking sheet in the oven and preheat it to 400 degrees.
On the baking sheet, spread out the broccoli florets and lemon halves. Sprinkle with salt, pepper, and olive oil before distributing evenly on the baking sheet.
Roast for 15 to 22 minutes, or until the edges are browned. Add some red pepper flakes and a squeeze of lemon juice to the broccoli, if preferred.