Bring a large saucepan of salted water to a boil. Add the broccoli rabe and cook until tender, about 3 minutes. Drain, squeezing to remove any excess water.
Heat the jelly in a small saucepan over low heat for 2 to 3 minutes. Remove from heat. Add the red pepper and mustard. Whisking constantly, slowly add the oil. Season with the salt and black pepper. Transfer the broccoli rabe to a serving bowl, drizzle with the jelly vinaigrette, and toss. Serve hot or at room temperature.