Scalloped Potatoes (Au Gratin)

• 4 large russet potatoes, peeled, washed and sliced into 1/4-inch thick
• 3 tablespoons butter, plus more for baking dish
• 1 white onion, cut into thin strips (Lyonnaise-style cut)
• 2 large garlic cloves, pressed
• 2 cups cold half-and-half cream
• 2 1/2 cups shredded aged cheddar cheese (mixed yellow and white)
• 2 teaspoons cornstarch (mixed with 1/2 cup water)
• 1/2 tablespoon cayenne (to taste)
• 1/2 tablespoon fresh ground black pepper (to taste)

1. Preheat oven to 400u0b0F and generously butter a 3-quart (9 x 13-inch) casserole dish. Layer 1/2 of the potato sliced into bottom. In a medium-size saucepan over medium heat, melt butter and saute onion with garlic for 3 minutes. Using a slotted spoon, transfer onion mixture over the potatoes in the prepared casserole dish; set aside.
2. Return saucepan to stovetop and pour cold milk. Bring to a simmer and add cheese, stirring until cheese has melted completely. Pour cornstarch mixture and stir until sauce thickens. Pour 1/2 cheese sauce over onion mixture and season with black pepper and cayenne. Add the remaining potatoes and pour the remaining sauce; season with black pepper and cayenne once again. Cover dish with greased aluminum foil and bake 1 1/2 hours in the preheated oven. Remove foil for the last 15 minutes for golden brown top.
3. Note: Sprinkle with Panko(R) for extra crispiness or use green onions and, crumbled and cooked bacon.

russet potatoes, butter, white onion, garlic, cold half, shredded aged, cornstarch, cayenne, fresh ground black pepper

Taken from www.food.com/recipe/scalloped-potatoes-au-gratin-535500 (may not work)