Final answer:
A food handler combining sliced raw potatoes with a heavy cream sauce is using the scalloping preparation method, often resulting in a dish called scalloped potatoes.
Step-by-step explanation:
When a food handler combines sliced raw potatoes with a heavy cream sauce, this preparation method is referred to as scalloping. This is often part of creating a dish known as scalloped potatoes, which involves layering slices of potatoes with cream sauce and often cheese before baking. While it could involve a pre-bake or pre-cook of the potatoes, the distinctive aspect of scalloping is the creamy sauce that accompanies the potatoes in the baking dish.