Preheat the oven to 375 degrees F. Toss the broccoli rabe, tomatoes and shallots in enough olive oil to thoroughly coat. Sprinkle with some salt and pepper. Spread the vegetables onto 2 large baking sheets (avoid crowding the sheets). Roast until the tomatoes have burst and the broccoli rabe is browned around the edges and cooked through, about 25 minutes. Transfer to a platter or large bowl to serve.