Parmesan Potato Gratin

1 Tbsp. olive oil
1 lb. chunk Parmesan
4 slices bacon, crisp-cooked and crumbled
2 green onions, thinly sliced
2 Tbsp. snipped fresh chives
4 lbs. potatoes, peeled and finely sliced
1 Tbsp. snipped fresh thyme
1 Tbsp. snipped fresh rosemary
1/4 cup unsalted butter, cut in small cubes
3/4 cup whole milk
3/4 cup heavy cream
3 Tbsp. all-purpose flour

1. Pre-heat oven to 325. Brush the bottom of a 3-quart rectangular or oval baking dish with olive oil. Using a wide vegetable peeler, shave Parmesan into thin strips.
2. In a small bowl combine bacon, green onion, and chives. In prepared baking dish, place half the potatoes. Sprinkle with 1/2 tsp each salt and freshly ground black pepper, half the bacon mixture, and half the herbs. Top with half the Parmesan and dot with half the butter. Repeat layers. In a small bowl whisk together whole milk, heavy cream, and flour; pour evenly over potatoes.
3. Bake, covered, for 1 1/2 hours. Increase temperature to 400 and bake uncovered for another 15-20 minutes or until potatoes are tender and top is golden brown.