Trim the tough ends of the broccoli rabe
Rinse it well
Bring a large pot of salted water to a boil
Blanch the broccoli rabe for 1 to 2 minutes
Drain and transfer it to ice water
Drain again and squeeze out excess water
Heat olive oil in a skillet over medium heat
Add sliced garlic and red pepper flakes
Cook until the garlic is fragrant
Add the broccoli rabe to the skillet
Toss and cook until heated through
Season with salt and black pepper
Add lemon juice if desired
Serve hot