Ingredients

• 0.25 cups unsalted butter
• 1 cup diced yellow onion
• 0.25 cups all-purpose flour
• 2 cups heavy cream
• 2 cups whole milk
• 2 teaspoons kosher salt , divided, or to taste
• 0.5 teaspoons freshly ground black pepper
• 0.25 teaspoons cayenne pepper
• 0.13 teaspoons freshly grated nutmeg
• 0.25 teaspoons Worcestershire sauce
• 2 teaspoons chopped fresh thyme leaves
• 4.5 pounds russet potatoes , peeled and sliced 1/4 inch thick
• 8 ounces grated sharp white Cheddar cheese
• 1 pound thinly sliced ham

Instructions

1. 1 Gather ingredients. Preheat the oven to 350 degrees F (175 degrees C).
2. 2 Heat butter in a pot over medium heat. Add onions and sauté with a pinch of salt until translucent, about 5 minutes.
3. 3 Add flour and cook, stirring, just to take off that starchy, raw edge, about 2 minutes.
4. 4 Pour in heavy cream and whisk to combine. Whisk in milk. Cook, stirring, over medium-high heat until it just starts to simmer and thicken up.
5. 5 Add 1 teaspoon salt, pepper, and cayenne. Grate in nutmeg.
6. 6 Turn off heat. Stir in Worcestershire and fresh thyme leaves. Reserve until needed.
7. 7 Cover the bottom of a deep 10x15-inch casserole dish with about 25% of the reserved sauce.
8. 8 Add a layer of sliced potatoes, seasoning the tops with some of the remaining salt as desired; ladle over 1/3 of the sauce and sprinkle over 1/3 of the grated Cheddar cheese. Layer in ½ of the sliced ham.
9. 9 Place another layer of sliced potatoes on top and season with salt. Ladle over ½ of the remaining sauce; repeat layering with Cheddar cheese and ham.
10. 10 Place last layer of potatoes on top. Ladle over remaining sauce and spread out with a spatula. Sprinkle over remaining Cheddar cheese.
11. 11 Bake uncovered in the preheated oven until browned, bubbling, and potatoes are very tender, about 1 ½ hours. Let cool for 15 to 20 minutes before serving.

Nutrition per serving