Combine one head lettuce, one head cauliflower, bacon, and Parmesan cheese in a large bowl.
To prepare the dressing, mix mayonnaise, bacon grease, sugar, and vinegar in a separate dish.
Add dressing to the salad bowl prior to serving, mixing everything well to combine.
Notes
The dressing can be made a day in advance and stored in the refrigerator. However, do not mix it with the salad until you are ready to serve it or the texture will turn soft.