Broccoli and Cauliflower Salad

I am not a fan of broccoli or cauliflower...but love this salad!!!

1 head broccoli - chopped into bite size pieces
1 head cauliflower - chopped into bite size pieces
¼ c. chopped onion
1 lb. fried bacon - or you can use the bacon already cooked (not bacon bits)
Mix together in bowl and set aside.
Dressing:
2 c. mayo
¼ c. Parmesan cheese
¼ c. sugar
¼ t. salt
2 T. vinegar
Mix together and toss with broccoli mix.
Transfer to 9x13 casserole dish.
Top with 8 oz. mozzarella cheese.