Ingredients
12 TBsp (1 1/2 sticks) butter, divided
2 lbs onions, sliced
2 TBsp (packed) chopped fresh thyme
4 tsp fine sea salt, divided
2/3 cup water
2/3 cup dry white wine
4 tsp sugar
2 1/2 lbs Yukon Gold, yellow Finn, or German Butterball potatoes, peeled, cut into 1/4-inch-thick rounds
2 lbs...