Makes 10 Servings
12 ounces bacon slices, chopped
2-1/2 cups whipping cream
1-1/2 cups whole milk
3-1/2 pounds Yukon gold potatoes, sliced into rounds
1-1/2 teaspoon salt
1 teaspoon freshly ground black pepper
8 ounces arugula, trimmed and coarsely chopped
1 cups grated Gruyere cheese, grated
Preheat over to 375F. Butter 13x9x2 inch baking dish. Cook bacon in a large skillet over medium high heat until crisp. Transfer bacon to paper towels and drain.
Mix cream and milk in a 4-cup measuring cup. Layer 1/3 of potatoes in prepared dish, overlapping slightly. Sprinkle with 1/2 teaspoon salt and 1/3 teaspoon pepper. Top potatoes with half the arugula, 1/3 of the cheese and 1/3 the bacon. Pour 1 cup cream mixture over potatoes. Repeat with next layer. Top with remaining layers, 1/2 teaspoon salt and 1/4 teaspoon pepper, remaining cheese and bacon. Pour remaining cream mixture over top.
Back gratin uncovered until potatoes are tender and cream thickens, about 1 hour and 15 minutes. Let stand 15 minutes before serving. (Can be made 1 day ahead. Cool slightly, chill uncovered until cold, then cover. Reheat, covered with foil in 375F oven for about 30 minutes).