Combine the Salad Base: In a large mixing bowl, combine the chopped broccoli florets, thick-shredded cheddar cheese, dried cranberries, crumbled bacon, sunflower seeds, and finely diced red onion.

Whisk the Dressing: In a separate, small bowl, whisk together the mayonnaise, sour cream, white wine vinegar, sugar, salt, and pepper until the mixture is completely smooth and well-combined.

Toss to Coat: Pour the creamy dressing over the broccoli combination. Toss and stir well until every ingredient is generously coated. Taste and adjust salt and pepper if necessary.

Chill and Serve: You can serve this salad immediately, but for the absolute best flavor, cover the bowl and refrigerate for at least one hour before serving.

Final Toss: Make sure to give the broccoli salad one more thorough toss right before serving to redistribute the dressing. Refrigerate any leftovers in an airtight container.