Preheat & Prepare: Preheat your oven to 375°F (190°C). Generously grease a 9x9 inch baking dish or a standard muffin tin for individual stacks.

Prepare Potatoes: Slice the potatoes thinly (exactly ⅛ inch) for even cooking using a mandoline slicer. Toss the slices lightly with the olive oil, ½ teaspoon salt, and ¼ teaspoon black pepper.

Make the Creamy Cheese Mixture: In a small saucepan, heat the heavy cream and minced garlic over medium heat just until warm. Remove from the heat and stir in the cheddar, Parmesan, and fresh thyme (if using). Season lightly with a pinch of salt and pepper.

Assemble Potato Stacks: Layer the potato slices in uniform stacks (about 5–6 slices per stack) inside the prepared dish or muffin tin. Spoon a little of the cheese mixture between each layer for extra creaminess. Repeat until all slices are used, finishing with a generous layer of the cheese mixture on top.

Bake: Cover the pan loosely with aluminum foil and bake for 25 minutes. Remove the foil and bake for 10–15 minutes more, or until the tops are deeply golden brown and bubbling.

Serve: Let the hot stacks rest in the pan for 5 minutes before carefully removing them to serve. Garnish with chopped fresh parsley or extra cheese if desired.