Ingredients
- 2 lbs (about 4–5 medium) Yukon Gold or Russet potatoes, peeled and thinly sliced (⅛ inch)
- 2 tbsp unsalted butter
- 2 tbsp all-purpose flour
- 2 cups whole milk (warm)
- 1 cup heavy cream
- 1½ cups shredded sharp cheddar cheese
- ½ cup grated Parmesan cheese
- 2 cloves garlic, minced
- 1 small onion, finely chopped (optional)
- 1 tsp salt
- ½ tsp black pepper
- ½ tsp dried thyme or 1 tsp fresh thyme
- Pinch of nutmeg (optional)
- Chopped fresh parsley (for garnish)
Instructions
- Preheat oven to 375°F (190°C). Grease a 9×13-inch baking dish with butter or nonstick spray.
- In a saucepan over medium heat, melt butter. Add onions (if using) and cook until softened, 3–4 minutes. Stir in garlic and cook another 30 seconds.
- Sprinkle in flour and whisk constantly for about 1 minute to make a roux.
- Slowly whisk in the warm milk and cream. Stir continuously until the sauce thickens, 3–5 minutes.
- Stir in salt, pepper, thyme, nutmeg, cheddar cheese, and half of the Parmesan. Remove from heat when the cheese is melted and smooth.
- Layer half of the sliced potatoes in the baking dish. Pour half of the cheese sauce over them.
- Repeat with the remaining potatoes and pour the rest of the sauce evenly on top.
- Sprinkle the remaining Parmesan cheese on top.
- Cover loosely with foil and bake for 40 minutes. Then remove foil and bake uncovered for another 25–30 minutes until bubbly and golden brown on top.
- Let rest for 10 minutes before serving. Garnish with fresh parsley.
Let me know if you’d like a version with bacon, ham, or a gluten-free option!