Broccoli raab is often used steamed or lightly sauteed in olive oil. Some like to give it a quick blanching to minimize the bitterness.
To prepare broccoli raab, trim the bottom 1/2 inch off the stems, then roughly chop, using stems, leaves and flowers together. Blanch in salted boiling water for 2 minutes if desired, then plunge into an ice water bath to stop the cooking. A simple way to enjoy it is to then lightly saute sliced or chopped garlic in olive oil for just a minute or so. Add the broccoli raab to the pan, and keep stirring until wilted and the stems are to desired tenderness. Add salt and pepper to taste. It can be enjoyed this way, or a squeeze of lemon juice, or drizzle of balsamic vinegar add a nice acidic punch. A sprinkle of good quality parmesan or romano cheese is also tasty, as is a sprinkle of red pepper flakes.