In a large bowl, combine broccoli, bacon, cranberries, sunflower seeds and red onion. Toss to combine. Set aside.
In a medium bowl, whisk together mayonnaise, cider vinegar, sugar, ½ teaspoon salt, and ¼ teaspoon black pepper.
Add the dressing to the broccoli mixture and toss to coat. Refrigerate for at least 3 hours. Stir the salad and season to taste with salt and black pepper before serving.
