Preheat the oven to 375°F.

Grease a 12-cavity muffin pan liberally with the softened butter.

Slice the potatoes a scant 1/8 inch thick and place in a large mixing bowl. Sprinkle with the garlic powder, salt, and black pepper.

Stack an even amount of potato slices in each muffin cavity. Pour 1 tablespoon of heavy cream over each potato stack.

Sprinkle a generous teaspoon of Parmesan cheese and a few leaves of fresh thyme over each potato stack.

Bake the individual gratins on middle rack of oven until bubbling and browned on the tops, 22-25 minutes.

Check to see that gratins are done. Remove from oven or add time as needed.

Allow the gratins to cool in the pan for 5 minutes. To remove, run a sharp knife around the edge of each individual gratin and lift up at an angle. Plate and serve immediately.