Ingredients:
- 3 lbs Yukon Gold potatoes, scrubbed and sliced 1/8 inch thick
- 1 tbsp unsalted butter
- 2 cups whole milk
- 0.5 cup heavy cream
- 3 cloves garlic, smashed
- 4 sprigs fresh thyme
- 0.5 tsp freshly grated nutmeg
- 1.5 tsp sea salt
- 0.5 tsp cracked black pepper
- 1.5 cups sharp white cheddar, shredded
- 0.5 cup Gruyere or Parmesan, finely grated
Instructions:
- Prep the environment. Preheat your oven to 375°F (190°C) and grease your 9x13 inch ceramic dish with that tablespoon of butter. Note: Thoroughly coating the corners prevents the cheese from welding to the dish.
- Infuse the liquid. Combine the 2 cups milk, 0.5 cup heavy cream, smashed garlic, thyme, nutmeg, salt, and pepper in a large saucepan. Bring it to a gentle simmer over medium heat — don't let it boil over!
- Steep the aromatics. Remove the pan from the heat and let it sit for 10 minutes. Note: This step is where the magic happens; the flavors seep into the fat during this rest period.
- Par cook the potatoes. Discard the thyme and garlic. Add the 3 lbs of sliced potatoes to the warm milk. Simmer gently on medium low for 5 minutes until the liquid looks slightly thickened.
- Build the first layer. Use a slotted spoon to move half of those warm potatoes into your baking dish. Spread them out so they are relatively flat and even.
- Add the cheese core. Sprinkle 0.75 cups of the shredded white cheddar over that first layer of potatoes. Note: This creates a glue that keeps the layers from sliding apart when you slice into them.
- Final assembly. Layer the rest of the potatoes on top. Pour all that remaining milk infusion over everything. Top with the rest of the cheddar and the Gruyere or Parmesan.
- The covered bake. Wrap the dish tightly in foil. Bake for 30 minutes until the potatoes are beginning to soften in their cream bath.
- The uncovered finish. Remove the foil and bake for another 30-35 minutes until the top is deeply golden and the sauce is bubbling frantically around the edges.
- The critical rest. Take the dish out and let it sit for 10 minutes before serving. Note: This allows the sauce to thicken into a velvety coating rather than being a runny soup.