1. Rinse the broccoli and cauliflower, pat dry, and cut into small bite size florets. Finely chop the red onion and place all the vegetables in a large mixing bowl.

2. Cook the bacon in a skillet over medium heat until very crisp, then drain on paper towels and crumble into small pieces. Set aside.

3. In a separate medium bowl, whisk together the mayonnaise, sour cream, sugar, apple cider vinegar, Dijon mustard, salt, and black pepper until smooth and creamy.

4. Pour the dressing over the broccoli, cauliflower, and red onion. Add the shredded cheddar cheese, sunflower seeds, and raisins or dried cranberries if using.

5. Gently toss until all of the vegetables and mix ins are evenly coated in the dressing. Fold in most of the crumbled bacon, reserving a small handful for topping.

6. Transfer the salad to a serving bowl, sprinkle with the reserved bacon and a little extra cheddar if desired, cover, and refrigerate for at least 1 hour to chill and let the flavors develop.

7. Before serving, stir the salad, taste, and adjust the seasoning with a pinch more salt, pepper, or a small splash of vinegar if needed. Serve chilled.