Caramelized Onion Potatoes au Gratin

Ingredients:

• 4 tablespoons unsalted butter, divided
• 2 sweet yellow onions, thinly sliced
• 1 teaspoon sugar
• 4 lbs (about 4-5 large) russet potatoes, peeled and sliced about 1/8" thick (3mm) on a mandoline
• 2 1/2 cups heavy cream
• 1 1/2 cups half & half
• 3 garlic cloves, grated
• 2-3 sprigs fresh thyme
• 2 bay leaves
• Pinch of nutmeg
• 6 oz gruyere cheese, shredded
• Kosher salt
• Freshly ground pepper

Instructions:

1. Caramelize the Onions:

• In a medium skillet, melt 2 tablespoons of butter over medium-low heat.
• Add the sliced onions and toss to coat. Season with salt and pepper.
• Cook, stirring occasionally, until the onions start to turn golden brown.
• Sprinkle the onions with 1 teaspoon of sugar and continue to cook until they are deeply amber in color. Set aside to cool.

2. Prepare the Potatoes:

• In a 4 qt pot or Dutch oven, combine the heavy cream, half & half, grated garlic, fresh thyme, bay leaves, and a pinch of nutmeg.
• Season with salt and pepper.
• Add the sliced potatoes and bring to a gentle simmer over low heat. Simmer for about 15 minutes, or until the potatoes start to become tender.
• Taste and season with more salt and pepper if needed. Remove from heat and let it rest for 10 minutes.

3. Preheat the Oven:

• Preheat your oven to 375°F (190°C). Butter a 3 qt baking dish with the remaining 2 tablespoons of butter and set aside.

4. Assemble the Dish:

• Discard the thyme sprigs and bay leaves from the potato mixture.
• Using a slotted spoon, transfer half of the potatoes to the prepared baking dish.
• Layer in half of the caramelized onions and half of the shredded gruyere cheese.
• Top with the remaining potatoes and pour the remaining creamy sauce from the pot over the top.
• Layer the remaining onions and cheese on top.

5. Bake:

• Bake the scalloped potatoes uncovered for 35-40 minutes, until the cheese is bubbly, golden brown, and the potatoes are tender.

6. Rest and Serve:

• Let the potatoes rest for 15 minutes before serving.
• Optionally, top with more fresh thyme for garnish.

Enjoy your rich and creamy Gruyère Scalloped Potatoes with Caramelized Onions!