Instructions

1. In a large skillet, on low to medium heat, add butter. Once melted, add in yellow onions. Sauté for at least 45 minutes, stirring often to ensure they caramelize evenly. The key to this is low and slow. If they begin to get too dry then add in a tablespoon of water. Once they begin to become golden in color, add in garlic, some leaves from one of your sprigs of thyme and a sprinkle of salt and sauté until done. Set to the side once done.
2. While the onions are cooking, peel the potatoes and add them into a large pot. Fill with water, at least 2 inches above potatoes. Boil for 20 minutes or so depending on size. Just until they are almost soft to the fork. They will cook some more in the oven. Once done, drain and allow them to cool to the touch. Once they have cooled, thinly slice them. Roughly 1/4 inch thick.
3. Preheat oven to 375 degrees.
4. In a medium bowl, mix your heavy cream, whole milk, salt, and nutmeg together.
5. Lightly Grease or Butter your baking dish. You will need to form 4 layers of potatoes, so use what will work best for that. Note: If you can place you 3lb bag of potatoes in it comfortably flat, then you’ve got a winner.
6. Place the first 2 layers of your sliced potatoes in your baking dish. Pour half of your milk mixture over the potatoes. Sprinkle with half of your Gruyere Cheese, a few slices of brie (leave most of it for the top) and half of your caramelized onions. Now repeat this step placing the rest of your ingredients on the top layer with a few more leaves of thyme.
7. Place baking dish on center rack of oven and bake for 30 – 40 minutes. Cook until the brie is bubbly and slightly golden. If your onions begin to crisp too much, then cover lightly with aluminum foil.
8. Once done, serve and enjoy!