This is a simple recipe from a 'French Country' cookbook. A couple of nice twists to try: substitute some or all of the potatoes for other root vegetables, like turnips, parsnips, celery root, etc. Also, substituting all or part of the cheddar cheese for other types - gruyere, blue, etc.
1 or 2 cloves garlic
1 pint half & half (or milk)
1 teaspoon salt
1 teaspoon black pepper
1/2 teaspoon nutmeg
dash cayenne pepper
dash paprika
4-5 russet potatoes, thinly sliced
1 cup cheddar cheese, grated
Rub the bottom of a 2 qt. casserole dish with the cut clove of garlic. Chop the remaining garlic, and add it plus the other ingredients except the paprika and cheese to a saucepan and heat over medium heat until the mixture simmers and thickens, stirring constantly to prevent sticking. Remove from heat and stir in 1/2 of the cheese.
Butter the bottom and sides of the casserole dish and add the mixture. Top with the rest of the cheese, dust with a little paprika, and bake at 350° for 45 minutes or until the mixture is bubbly and cheese topping has browned.