Wipe out the saucepan. Add the olive oil and pancetta and cook over moderately low heat, stirring often, until the pancetta is golden, 8 to 10 minutes. Add the garlic and cook, stirring, until golden, about 3 minutes. Add the broccoli rabe, season with salt and pepper and cook over moderately high heat until tender, 3 to 4 minutes. Transfer the broccoli rabe to a bowl and serve.