Step 1: Prepare the broccoli. Wash the broccoli heads thoroughly. Trim off the thick, woody stems and cut the broccoli into small, bite-sized florets. Ensure they are uniform in size for even eating. Place the florets into a large mixing bowl.
Step 2: Add the remaining solid ingredients. To the bowl with the broccoli, add the finely chopped red onion (if using), dried cranberries, and roasted sunflower seeds.
Step 3: Prepare the creamy dressing. In a separate, smaller bowl, whisk together the mayonnaise, apple cider vinegar, granulated sugar, salt, and black pepper until the dressing is completely smooth and well combined. Taste and adjust seasoning as desired.
Step 4: Combine and coat. Pour the creamy dressing over the broccoli mixture in the large bowl. Using a spatula or large spoon, gently fold and toss all the ingredients together until the broccoli florets, cranberries, and sunflower seeds are evenly coated with the dressing.
Step 5: Chill the salad. Cover the bowl with plastic wrap and refrigerate for at least 1 hour. Chilling allows the flavors of the cold broccoli salad to meld beautifully and the broccoli to slightly tenderize, enhancing the overall taste and texture. For best results, chill for 2-3 hours.
Step 6: Serve and enjoy! Before serving, give the cold broccoli salad another good stir. You can garnish with a sprinkle of extra sunflower seeds or fresh chopped parsley if you wish. Serve cold and enjoy this delicious, easy side dish!