Trim broccoli rabe; cut into 3-inch-long pieces. Cook in boiling water 1 1/2 minutes; drain and rinse. Drain well. Heat olive oil and butter in a skillet over medium-high heat. Add onion; sauté 2 minutes or until lightly browned. Add broccoli rabe; sprinkle with salt, and toss to combine. Cook 1 minute. Sprinkle with pine nuts.