Set a medium-sized saucepan filled with 1 inch of water over high heat, and bring the water to a boil. Place the broccoli in a steamer basket, place inside of the saucepan , cover and reduce the heat to medium. Steam the broccoli until just tender when pierced with a fork, 4 to 5 minutes. Transfer the broccoli to a serving bowl. Add the olive oil, grate the zest of the lemon over the broccoli, sprinkle with salt and pepper, and toss to coat. Serve.