In a large mixing bowl, combine the chopped broccoli florets, cauliflower florets, diced red onion, shredded cheddar cheese, sunflower seeds, and crumbled bacon. Gently toss to distribute all the evenly.
To make the dressing, whisk together the mayonnaise, granular erythritol, and apple cider vinegar in a separate small bowl until smooth and the sweetener has dissolved.
Pour the dressing over the broccoli mixture and toss everything together until the salad is evenly coated.
Cover the bowl and refrigerate for at least 4 hours, or preferably overnight. This chilling time is crucial for the flavors to meld together.
Serve chilled.
Don't skip the chilling time!
Letting the salad rest for at least 4 hours allows the dressing to soften the veggies slightly and all the flavors to meld together beautifully.