Preheat oven to 325 degrees. Spray a 1 ½ quart casserole pan.
Layer half the potato slices in the bottom of the casserole dish. Dot with half of the butter. Arrange half of the garlic slices over the potatoes, then pour half of the heavy cream over. Sprinkle one cup of cheddar cheese over the layer, and season with salt and pepper. Repeat layering of potatoes, garlic, cream and cheese. Season again with salt and pepper.
Bake covered for ½ hour in the preheated oven, then sprinkle Parmesan cheese over the top. Continue baking uncovered for 50-60 minutes.
