Bring a large pot of salted water to a boil. Boil the broccoli rabe for 3 minutes, then drain.
In a large, deep skillet over medium heat, heat enough olive oil to nicely coat the bottom of the pan, 1 to 2 tablespoons. Stir in the garlic and cook for 30 seconds, then stir in the red-pepper flakes.
Add the broccoli rabe and sauté, shaking the pan and gently tossing so that it cooks evenly, until tender (especially the stems), 3 to 5 minutes.
Remove the broccoli rabe from the pan and drain off any excess liquid. Arrange the broccoli on a plate or platter. Tear the burrata and scatter the pieces among the broccoli rabe. Sprinkle with lemon juice, pistachios and salt. Drizzle with olive oil, if desired, and serve.
