1. Thinly slice the clean (or peeled) potatoes and place in a large stock pot. Cover with water and bring to a boil.

2. Simmer just until potato slices are tender -- about 5-15 minutes depending on the type of potato and how thinly they were sliced. (I use a "Salad Shooter" which makes very thin slices!) test the potatoes as they cook to avoid over-cooking. the slices should be soft but NOT mushy, or you will end up with scalloped mashed potatoes! ;)

3. Drain potatoes. In the now-empty stock pot, heat butter over medium heat. If using freshly chopped onions, add them to the butter and saute until tender. Otherwise, just melt the butter and then stir in the flour.

4. When the flour is completely incorporated into the butter, add the milk and stir or whisk until the milk boils and thickens slightly. You can go ahead and add the garlic salt, dried/powdered onion (if not using fresh), and pepper while you're bringing the milk to a boil.

5. Remove the thikened milk mixture from the heat, and stir in the shredded cheese, sour cream, and 3/4 teaspoon salt. If the cheese doesn't completely melt, that's okay.

6. Place the drained potato slices in a large mixing bowl and pour the cheese sauce mixture over the potatoes. Gently fold the cheese sauce into the potatoes. I always taste the potatoes at this point to make sure the salt is to my liking. Not enough salt makes this dish taste bland! The perfect amount of salt makes it taste fabulous! :)

7. Pour the potatoes into a greased 9x13-inch baking dish, spreading evenly. Bake at 350 degrees until hot and bubbly!