Bring a pot of water to a boil and cut off the bottom 1/2 inch or so of the broccoli. Blanche the broccoli rabe for 2-3 minutes in the boiling water.
Remove the broccoli from the pot and dry it on a paper towel.
Over medium to high heat, warm up a pan with olive oil. Sauté the broccoli rabe for 5-8 minutes with the red pepper flakes, salt, and pepper. Squeeze some lemon juice over the broccoli while it’s cooking and serve.