Chop broccoli and cauliflower into small pieces. In a large bowl, combine chopped broccoli, cauliflower, cheese and chopped onion. Toss until well combined.
In a small bowl, mix mayonnaise, erythritol and vinegar. Stir to blend well.
Pour dressing over veggies and stir until the veggies are evenly coated in dressing. Cover and refrigerate for at least one hour.
Right before serving, sprinkled with crumbled bacon and sunflower seeds.
I highly suggest using Hellman's mayonnaise for this recipe. I've never tested it using a different mayo, but know that Hellman's works well.If you aren't concerned with counting carbs, you can use regular, white sugar in place of the erythritol.