Take a large pot of salty water and bring it to a boil. Cook broccoli rabe in water for 3 to 5 minutes until tender and bright green. Drain well in a colander and set aside. In a large saute pan heat a 2 count of extra-virgin olive oil over medium heat. Add the garlic and pepper flakes then toss in the broccoli rabe. Season with salt and pepper and cook for 2 to 3 minutes, gently tossing it in the pan. Finish with the lemon zest and toss to combine. The broccoli rabe should be tender and fragrant with lemon when done. Give it 1 final taste and season, if necessary. Serve immediately.