Ingredients

1 cup whole milk

6 sprigs thyme

2 dried bay leaves

6 tablespoons (3/4 stick) unsalted butter, divided, plus more for pan

Kosher salt

Freshly ground black pepper

4 lb. Yukon gold potatoes, peeled and cut into 1″ pieces

3 cloves garlic, smashed and peeled

8 oz. cream cheese, room temperature

1/2 cup finely grated Parmesan (about 2 oz.), divided

2 large eggs, beaten to blend

1 cup panko bread crumbs

Sliced chives, for serving

Instructions

Step 1: In a medium saucepan over medium heat, bring the milk, thyme, bay leaves, 4 tablespoons butter, 1/2 teaspoon salt, and 1/4 teaspoon black pepper to a simmer. Remove from heat, cover, and let the mixture stand for 1 hour to infuse the flavors.

Step 2: Preheat your oven to 375°F (190°C). Grease a 2 1/2- to 3-quart baking dish with butter to prevent sticking.

Step 3: In a large pot, combine the potatoes and garlic. Cover with at least 2 inches of water and season with 2 tablespoons salt. Bring to a boil and cook until the potatoes are fork-tender, about 12 to 15 minutes. Reserve 3/4 cup of the cooking liquid, then drain the potatoes and garlic. Return them to the pot and mash until smooth.

Step 4: Return the infused milk to a bare simmer over medium heat, then discard the thyme and bay leaves. Stir in the cream cheese and 1/4 cup Parmesan until melted and smooth. Add this mixture to the mashed potatoes along with the beaten eggs. If needed, add the reserved cooking liquid gradually until the consistency is thick but spreadable. Season with salt and pepper to taste. Transfer the mash to the prepared baking dish.

Step 5: In a small skillet over medium heat, melt the remaining 2 tablespoons of butter. Cook, swirling the pan, until the butter browns slightly and smells nutty, about 2 to 3 minutes. Remove from heat and stir in the panko bread crumbs and remaining 1/4 cup Parmesan. Season with salt and pepper, then sprinkle this topping evenly over the mashed potatoes. Cover the dish with foil.

Step 6: Bake the casserole covered for 10 minutes. Remove the foil and continue baking until the casserole is hot and the topping is golden brown, about 20 to 22 minutes. Garnish with sliced chives before serving.

Tips & Variations

For a richer flavor, use half-and-half instead of whole milk when infusing with herbs.

Swap the Parmesan for Gruyère or sharp cheddar for a different cheesy twist.

Add cooked crumbled bacon or caramelized onions to the mashed potatoes for extra depth.

Use fresh breadcrumbs instead of panko for a softer topping texture.

FAQs

Can I prepare this casserole ahead of time?

Yes, you can assemble the casserole up to a day in advance, cover it tightly, and refrigerate. Bake it when ready, adding a few extra minutes to the cooking time if baked cold.

Can I use different potatoes?

Yukon gold potatoes are recommended for their creamy texture, but russet potatoes can also work. Just note that russets may result in a lighter, fluffier mash.