How to Make It: Step-by-Step
Because these are baked in a muffin tin, proper pan preparation is the difference between an elegant presentation and a stuck-on cleanup disaster.
Preheat your oven to 375°F (190°C). Generously grease a standard 12-cup muffin tin with softened unsalted butter. For extra insurance against sticking, you can sprinkle a little bit of grated Parmesan cheese directly into the bottom of each greased cup.
Using a mandoline or a very sharp chef's knife, slice the peeled potatoes into uniform, paper-thin rounds. In a small bowl, whisk together the heavy cream, minced garlic, fresh thyme leaves, a generous teaspoon of salt, and plenty of cracked black pepper.
Place your potato slices into a large mixing bowl. Pour the seasoned cream mixture over them, along with half of the grated Gruyère and Parmesan. Use your hands to gently toss the slices, making sure every single piece is coated in cream and has a bit of cheese clinging to it.
Pick up small stacks of the coated potato slices and layer them flat into the muffin cups, filling them all the way to the top. Keep in mind that the potatoes will shrink and settle slightly as they bake, so it is perfectly fine to stack them slightly higher than the rim of the tin. Pour any remaining cream from the bottom of the bowl evenly over the tops of the stacks.
Cover the muffin tin loosely with a sheet of aluminum foil and bake for 20 minutes to let the centers tenderize. Remove the foil, sprinkle the remaining Gruyère and Parmesan over the top of each cup, and bake uncovered for another 10 to 15 minutes until the tops are deeply golden brown and bubbling.
The Golden Rule of Removal: Do not attempt to pull the gratin cups out of the tin the second they leave the oven! Let them rest undisturbed in the pan for 5 to 10 minutes. As they cool slightly, the cream thickens and the cheese solidifies, locking the layers together. Run a thin plastic spatula or butter knife around the edges of each cup to lift them out effortlessly.
.jpg)
