3 pounds Yukon Gold potatoes, peeled, cut into 1/8-inch-thick rounds
2 teaspoons salt
1 teaspoon ground black pepper
2 1/2 teaspoons dried tarragon
1 1/2 cups (packed) grated sharp white cheddar cheese (about 6 ounces)
1 cup whipping cream
1 cup dry white wine
Preheat oven to 400°F. Butter 13x9x2-inch glass baking dish. Layer 1/3 of potatoes in prepared dish, overlapping slightly. Sprinkle with 1/3 of salt and 1/3 of pepper. Sprinkle with 1/3 of tarragon, then with 1/3 of cheese. Repeat layering twice more with remaining potatoes, salt, pepper, tarragon, and cheese.
Whisk cream and wine in medium bowl to blend. Pour over potatoes. Bake uncovered until potatoes are tender when pierced with knife and top is golden, about 1 hour. Let gratin stand 5 minutes before serving.