Creating Scalloped Potatoes With Caramelized Onions is straightforward. Follow these detailed steps for success:

1. Preheat your oven: Set your oven to 375°F (190°C).
2. Prepare the potatoes: Peel and thinly slice the russet potatoes, about 1/8 inch thick. A mandoline can help achieve uniform slices.
3. Caramelize the onions: In a large skillet over medium heat, add olive oil and butter. Once hot, add thinly sliced onions. Cook for 15-20 minutes, stirring occasionally, until they’re soft and golden brown. Remove from heat and set aside.
4. Prepare the cream mixture: In a bowl, combine heavy cream, garlic powder, salt, pepper, and thyme. Mix well to ensure the seasonings are evenly distributed.
5. Layer the potatoes: In a greased baking dish, layer half of the sliced potatoes at the bottom. Pour half of the cream mixture over the potatoes. Then, add half of the caramelized onions.
6. Repeat layers: Add another layer of the remaining potatoes, followed by the rest of the cream mixture, and top with the remaining caramelized onions.
7. Top with cheese: Sprinkle the grated cheddar cheese evenly over the top.
8. Cover and bake: Cover the dish with aluminum foil and bake in the preheated oven for 45 minutes.
9. Brown the top: After 45 minutes, remove the foil and bake for an additional 15 minutes, or until the top is golden and bubbly.
10. Let it cool: Once baked, allow it to sit for about 10 minutes before serving, as this will help the layers set.