Preheat your oven to 350°F.
Peel yukon gold potatoes. I find a Y-peeler works best. Carefully cut them into thin slices using a sharp knife and a clean cutting board. You may also use a food processor with a slicing attachment or a mandoline with a finger guard.
2 lbs. Yukon Gold Potatoes
Place your potato slices in cold water for about 5 minutes. Give them a couple of tosses in the water, then drain the water. This will reduce excess starch in addition to cleaning up the potatoes.
Heat an oven-safe skillet on the stove and melt butter in it. A 10-inch skillet with 2-inch sides or similar works best.
1 Tbsp. unsalted butter
Once the butter melts, remove the skillet from the heat and add minced garlic. Stir the garlic around to coat it with the butter.
1 Tbsp. garlic
Spread half of the sliced potatoes in the bottom of the skillet. Top with heavy cream, Gruyere cheese, salt, pepper, half of your cubed butter, and thyme (if using).
1½ cups heavy whipping cream, ½ lb. Gruyere cheese, 3 Tbsp. unsalted butter, 2 tsp. fresh thyme leaves
For the next layer, add the remaining potatoes, cream, salt, pepper, butter, and thyme. Finish with remaining cheese on top.
1 tsp. kosher salt, ½ tsp. freshly cracked black pepper
Cover with aluminum foil or a pan lid. Bake for 1 hour.
Remove the foil and use a fork to check if the potatoes are tender. They are best when fork-tender but still with a little firmness to them. However, you can bake them a bit longer for softer potatoes, if you prefer them softer.
Once the potatoes are tender to your liking, remove the foil and continue to bake the gluten free au gratin potatoes for 15-20 minutes, or until the top develops a beautiful golden brown crust.
Allow the dish to rest for 10 minutes after removing from the oven. Serve, and enjoy!