Slice off the stem of the broccoli and chop the broccoli florets into small bite-size pieces. Repeat steps with the cauliflower, chopping into bite-sized pieces.
Cook 1 small package of regular sliced bacon until crispy. Add it to paper towel to absorb any excess grease. Crumble the bacon using your hands or a knife. Set aside.
In a medium bowl, mix together the dressing ingredients: 1 ½ cups mayonnaise, ½ cup sour cream, ¼ cup white vinegar, ¼ cup maple syrup.
In a large bowl, add the broccoli florets from the 2 large broccoli heads, cauliflower florets from 1 head of cauliflower, 1 cup chopped red onion, cooked crumbled bacon, and 2 ½ cups shredded cheddar cheese. Toss everything together.
Pour the salad dressing over top and mix together with the salad. Cover the bowl with plastic wrap and place in the fridge for 2-3 hours. Mix together again just before serving.