Serves: 8 people. Preparation time: 1 hour, 45 minutes.
Preheat the oven to 350°F. Wash, peel and slice the potatoes into thin ⅛" slices. For uniform results, you can use a "mandoline" if available. Then dice the slices into ⅛" cubes. Allow the pieces to dry on a towel for a while to help prevent a watered-down dish.
In a bowl, add the Butter, Cream/Milk and Garlic. Mix until combined.
In a large (1.5 Qt.) baking dish (coated with non-stick vegetable spray), spread about ⅓ of the Potato Cubes on the bottom, pour ⅓ of the Cream Mix over it, then Salt, Pepper and Thyme to taste. Cover with ¾ C. of Gruyere Cheese. Repeat the Potato/Cream/Spices/Cheese layer again. For the third (top) layer, repeat the Potato/Cream/Spices only (not the Cheese).
Cover with foil and bake for 1 hour and 15 minutes. Check that the Potato Cubes are soft with a fork. Bake 15 more minutes if necessary. Remove the foil, top with the remaining Cheese and bake an additional 10 minutes until golden brown. Let stand for 10 minutes before serving. Cut in squares for each portion.
Pommes au Gratin - Pronounced Pom aw Gra-tahn' . Here Pommes means Pommes de Terre (potatoes not apples). A popular French side dish served in squares. Also know as Pommes Anna or Scalloped Potatoes in the USA. A similar dish is Pommes Dauphinoise and Pommes Lyonnaise.