Preheat oven to 400 degrees Fahrenheit.

In a bowl, place potatoes and sprinkle with salt and pepper.

In a round nine-inch baking dish, line up potatoes in circles. (Or, in a square baking dish, line in rows.)

In a pot, place two cups cheese, milk, cornstarch, chicken soup mix, garlic cubes, salt, and pepper. On a medium-high flame, whisk mixture until smooth.

Pour cheese mixture over potatoes. Sprinkle remaining half cup cheese on top.

Bake covered for one hour, then uncovered for 30 minutes.