1 head cauliflower
1 bunch broccoli
1 lg. onion, sliced
1 pkg. buttermilk dressing mix
1 c. buttermilk
1 c. mayonnaise

Cut cauliflower into bite-size pieces. Cut end stem, broccoli using flowerets only. Add the onion. Mix last three ingredients. Pour over vegetables and tops lightly. Refrigerate for 3 to 4 hours before serving.