Cook 8 ounces of bacon in a skillet over medium heat until crisp, or bake it at 400°F for approximately 15–20 minutes. Drain well on paper towels, cool completely, and crumble.

Wash the broccoli and cauliflower, then dry them thoroughly. Cut both vegetables into small, bite-size florets so the salad is easy to scoop and serve.

Place the broccoli, cauliflower, red onion, shredded cheddar, crumbled bacon, and sunflower seeds in a large mixing bowl. Reserve a little bacon and sunflower seed for topping if desired.

In a separate bowl, whisk the mayonnaise, sour cream, sugar, apple-cider vinegar, salt, and black pepper until smooth and creamy.

Pour the dressing over the vegetable mixture and toss gently until every piece is lightly coated. Avoid crushing the florets or stirring too aggressively.

Cover the bowl and refrigerate for at least 1 hour, although 2–4 hours gives the best flavor. Toss again just before serving and adjust the salt or vinegar if needed.