Preheat oven to 350F. Spray a standard 12 muffin tin with oil. Peel then slice potatoes into thin slices. Place butter and garlic in a microwave proof bowl, then melt in 30 second bursts. Add cream, salt and pepper into the butter. Stir to dissolve the salt. Place potato slices into the muffin tin so they go halfway up the muffin tin. Drizzle each potato stack with ½ tsp of cream mixture then sprinkle with half the thyme. Sprinkle HALF the cheese over the potato stacks.
Top with remaining potato slices. Drizzle with remaining cream mixture and remaining thyme. Cover loosely with foil and bake for 35 minutes. Remove from oven, sprinkle with remaining cheese and bake without foil for 10 minutes or until golden and the potato is soft. Let stand for 5 minutes before removing. Use a tablespoon or butter knife to help scope them out.