Start by washing and peeling your russet potatoes. It’s essential to slice them thinly and evenly—about a quarter of an inch thick—so they cook uniformly. You can use a sharp knife for this, but a mandoline slicer will save you time and ensure even slices.

As you’re prepping the potatoes, go ahead and preheat your oven to 375°F (190°C). A hot oven is crucial for achieving that perfectly golden, bubbly top.

In a mixing bowl, combine the heavy cream, minced garlic, nutmeg, salt, and pepper. Whisk these together until well incorporated. Don't skip this step; the garlic really blends in the cream when combined this way, ensuring that flavor permeates throughout the bake.

Take a large baking dish and lightly grease it with butter. This will prevent your cheesy goodness from sticking. I usually use a 9x13 inch dish, but you can adjust based on how many guests you're serving.

Now it’s time to layer! Start with a layer of sliced potatoes on the bottom of the dish. Pour a portion of the cream mixture over the potatoes, followed by a sprinkle of Parmesan cheese and chopped thyme. Continue this layering process until you use all your potatoes, cream, and cheeses, finishing with a generous layer of the sharp white cheddar on top.

Cover the dish with aluminum foil, making sure it doesn’t touch the cheese. This keeps the moisture in while the potatoes cook. Bake for 45 minutes covered, then remove the foil and bake for an additional 20-30 minutes, or until the top is golden brown and the potatoes are tender when pierced with a fork.

Once out of the oven, let the dish sit for about 10 minutes. This helps everything set up nicely. Scoop onto plates and prepare for the compliments to roll in!