Apple, Potato, and Onion Gratin

Ingredients

• ²/₃ cup dry white wine
• 2 pounds onions
• 12 tablespoons butter
• 2 pounds tart apples (such as Granny Smith, Pippin, or Pink Lady)
• ²/₃ cup water
• 4 teaspoons sugar
• 2 ½ pounds Yukon Gold, yellow Finn, or German Butterball potatoes
• + 2 more ingredients
• • 4 teaspoons fine sea salt
  • 2 tablespoons fresh thyme

Preheat oven to 400°F. Butter 13x9x2-inch glass or ceramic baking dish. Melt 6 tablespoons butter in large nonstick skillet over medium heat. Add onions, thyme, and 2 teaspoons salt; sauté until onions are translucent, about 10 minutes. Increase heat to medium-high; sauté until onions are tender ...

View full recipe at Epicurious