1-Preheat oven to 400°F (200°C) and grease a 9×13-inch baking dish to get started on this tasty adventure.

2-Melt 3 tablespoons butter in a medium skillet over medium heat, then add flour and whisk constantly for 1 minute to form a base.

3-Slowly whisk in 1 cup whole milk, followed by 2 cups vegetable broth, until the mixture turns smooth and creamy.

4-Add 4 cloves grated garlic, 1 tablespoon chopped fresh thyme, 2 teaspoons salt, and 1/2 teaspoon pepper; cook for 2-3 minutes while stirring, until it thickens without boiling.

5-Layer half of the 3 pounds sliced Yukon Gold potatoes and 1/2 thinly sliced onion evenly in the prepared baking dish for even cooking.

6-Pour half of the sauce over the potato layer and sprinkle with 1 cup of the shredded cheddar cheese to lock in the flavors.

7-Repeat the layers with the remaining potatoes, onion, sauce, and the remaining 1/2 cup of cheese for a full, hearty dish.

8-Cover the dish and bake for 30 minutes to start the softening process.

9-Uncover and bake for an additional 35 to 40 minutes, until the potatoes are tender and the cheese turns browned and bubbly on top.

10-Remove from the oven and let stand at room temperature for 20 minutes before serving to let everything set perfectly. Check out our baking tips guide for even better results.