Two-Toned Scalloped Potatoes

Ingredients

• 1 ½ pounds Yukon Gold potatoes
• 1 ½ pounds sweet potatoes
• 2 cups heavy cream
• 2 tablespoons all-purpose flour
• 3 teaspoons fresh thyme, chopped
• 2 garlic cloves, chopped (1 to 1 1/2 tablespoon)
• ¼ cup plus 1 tablespoon unsalted butter, divided
• 2 teaspoons table salt, divided
• 1 teaspoon black pepper
• 2 tablespoons fresh flat-leaf parsley, chopped
• 1 tablespoon fresh rosemary, chopped
• 6 ounces Gruyère cheese, shredded with large grate (about 1 1/2 cups)
• ½ cup panko (Japanese-style breadcrumbs)
• ⅓ cup pecans, chopped
• 1 teaspoon lemon zest (from 1 lemon)

Instructions

1. Preheat your oven to 400°F. Lightly coat a 2- to 3-quart baking dish with cooking spray.
2. Peel potatoes and place them in a bowl of cold water. Using a mandoline, slice potatoes into 1/8-1/4 inch rounds. Return slices to cold water until ready to use.
3. Stir together heavy cream, flour, thyme, garlic, 1/4 cup of the butter, and 1 teaspoon of the salt in a medium sauce pan over medium. Bring just to a boil; remove from heat.
4. Combine pepper and remaining 1 teaspoon salt in a small bowl. Combine chopped parsley and rosemary in a second small bowl.
5. Drain sliced potatoes, and pat dry. Place half of the potato slices evenly into prepared baking dish. Sprinkle with 1 tablespoon of the chopped herbs, half of the salt-pepper mixture, and half of the cheese. Repeat process with remaining half potato slices, 1 tablespoon of the herbs, remaining salt-pepper mixture and cheese. Pour cream mixture evenly over potatoes. Cover with aluminum foil, and bake in preheated oven 25 minutes.
6. Stir together panko, pecans, lemon zest, and remaining 1 tablespoon herbs and 1 tablespoon melted butter in a small bowl until combined well. Uncover potatoes; sprinkle evenly with panko mixture. Bake another 20 to 25 minutes, or until topping is golden and mixture is bubbling. Let stand 10 to 15 minutes before serving.