Introduction

This Mashed Potato Casserole is a comforting, creamy dish with a cheesy, crunchy topping that makes it perfect for family dinners or holiday gatherings. Infused with garlic, thyme, and Parmesan, it brings a delicious twist to classic mashed potatoes.

Mashed Potato Casserole with Thyme, Parmesan, and Crispy Panko Topping Recipe - Recipe Image

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 pounds Yukon gold potatoes, peeled and cut into 1-inch pieces
3 cloves garlic, smashed and peeled
8 ounces cream cheese, room temperature
1/2 cup finely grated Parmesan (about 2 ounces), 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 of butter, 1/2 teaspoon salt, and 1/4 teaspoon pepper to a simmer. Remove from heat, cover, and let stand for 1 hour to infuse flavors.
Step 2: Preheat the oven to 375°F (190°C). Grease a 2 1/2- to 3-quart baking dish with butter.
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: Meanwhile, return the infused milk to a bare simmer over medium heat and discard the thyme and bay leaves. Add the cream cheese and 1/4 cup of Parmesan, stirring until smooth and melted. Pour this mixture into the mashed potatoes along with the beaten eggs. Gradually add the reserved cooking liquid as needed to achieve a thick but spreadable consistency. Season with salt and pepper. Transfer the mashed potato mixture to the prepared baking dish.
Step 5: In a small skillet over medium heat, melt the remaining 2 tablespoons butter. Cook, swirling the pan, until the butter starts to brown and smells nutty, about 2 to 3 minutes. Remove from heat and stir in the panko and remaining 1/4 cup Parmesan. Season with salt and pepper. Sprinkle this topping evenly over the mashed potatoes. Cover the pan with foil.
Step 6: Bake the casserole for 10 minutes covered. Then uncover 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 extra richness, stir in a splash of sour cream or a handful of shredded cheddar before baking.
Use red potatoes or Russets as a substitute for Yukon golds for a different texture and flavor.
Add crispy cooked bacon or sautéed mushrooms to the potato mixture for added depth.
To make it vegetarian, ensure your broth and butter substitutes contain no animal products.
Use fresh herbs like rosemary or parsley instead of thyme for a flavor variation.

Storage

Store leftover casserole covered in the refrigerator for up to 4 days. Reheat in the oven at 350°F (175°C) until warmed through, about 20 minutes, to preserve the crispy topping. You can also reheat individual portions in the microwave but the topping may lose some crunch.

How to Serve

Serve this delicious recipe with your favorite sides.

FAQs

Can I make this casserole ahead of time?

Yes, you can prepare the mashed potato mixture and topping ahead, assemble in the dish, cover, and refrigerate for up to 24 hours before baking. Adjust baking time to ensure it is heated through.

What can I use instead of panko bread crumbs?

If you don’t have panko, regular bread crumbs or crushed crackers work as a crunchy topping alternative, though panko provides the best texture.

Mashed Potato Casserole with Thyme, Parmesan, and Crispy Panko Topping Recipe

Print Recipe

★★★★★

4.8 from 72 reviews

This Mashed Potato Casserole elevates classic mashed potatoes with a creamy blend of cream cheese, Parmesan, and infused milk, topped with a buttery, golden panko crust. Perfectly comforting and rich, it’s an ideal side dish for holiday dinners or any cozy meal.

Author: Isabella
Prep Time: 15 minutes
Cook Time: 50 minutes
Total Time: 1 hour 5 minutes plus 1 hour infusion time
Yield: 8 servings 1x
Category: Side Dish
Method: Baking
Cuisine: American

Ingredients

Scale

Milk Mixture

1 cup whole milk
6 sprigs thyme
2 dried bay leaves
4 tablespoons (1/2 stick) unsalted butter
1/2 teaspoon kosher salt
1/4 teaspoon freshly ground black pepper

Potatoes and Mix-ins

4 pounds Yukon gold potatoes, peeled and cut into 1-inch pieces
3 cloves garlic, smashed and peeled
8 ounces cream cheese, room temperature
1/2 cup finely grated Parmesan (about 2 oz.), divided
2 large eggs, beaten to blend
Additional kosher salt and freshly ground black pepper, to taste

Topping

2 tablespoons (1/4 stick) unsalted butter
1 cup panko bread crumbs
1/4 cup finely grated Parmesan (remaining portion)
Sliced chives, for serving

Instructions

Infuse the Milk: In a medium saucepan over medium heat, combine milk, thyme sprigs, bay leaves, 4 tablespoons butter, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Bring mixture to a gentle simmer, then remove from heat, cover, and let it steep for 1 hour to infuse the flavors.
Prepare the Baking Dish: Preheat your oven to 375°F (190°C). Generously butter a 2.5- to 3-quart baking dish to prevent sticking and ensure an easy release after baking.
Cook the Potatoes and Garlic: In a large pot, place the peeled and chopped potatoes along with the smashed garlic cloves. Cover with water by at least 2 inches, season the water with 2 tablespoons kosher salt, and bring it to a boil. Cook until the potatoes are fork-tender, about 12 to 15 minutes.
Mash the Potatoes: Before draining, reserve 3/4 cup of the cooking liquid for later use. Drain the potatoes and garlic, then return them to the pot. Mash the potatoes and garlic smoothly using a potato masher.
Finish the Potato Mixture: Return the infused milk to a bare simmer over medium heat; remove and discard the thyme sprigs and bay leaves. Stir in the cream cheese and 1/4 cup Parmesan into the milk until fully melted and smooth. Pour this creamy mixture into the mashed potatoes, add the beaten eggs, and mix thoroughly. Adjust the consistency with the reserved cooking liquid to reach a thick but spreadable texture. Season well with salt and pepper.
Prepare the Topping: In a small skillet over medium heat, melt the remaining 2 tablespoons of butter. Cook the butter, swirling the pan, until it turns golden brown and emits a nutty aroma, about 2 to 3 minutes. Remove from heat, then stir in the panko bread crumbs and the remaining 1/4 cup Parmesan. Season with salt and pepper to taste.
Assemble and Bake: Spread the mashed potato mixture into the prepared baking dish. Evenly sprinkle the browned butter-panko topping over the potatoes. Cover the dish with foil.
Bake the Casserole: Place the casserole in the oven and bake covered for 10 minutes. Then remove the foil and continue baking until the casserole is thoroughly heated and the topping becomes golden brown and crisp, about 20 to 22 more minutes.
Garnish and Serve: Once baked, garnish with freshly sliced chives to add a fresh, mild onion flavor and a pop of color. Serve hot.

Notes

If you prefer a richer flavor, consider using half-and-half or heavy cream instead of whole milk, but adjust the fat content in nutrition accordingly.
For a gluten-free version, substitute panko bread crumbs with gluten-free bread crumbs or crushed gluten-free crackers.
Allow the casserole to rest for 5 minutes after baking for easier serving.
Leftovers can be stored covered in the refrigerator for up to 3 days and reheated in the oven to maintain crispiness of the topping.
Ensure the cream cheese is at room temperature to blend smoothly into the milk infusion.

Keywords: mashed potato casserole, creamy mashed potatoes, cheesy potato bake, buttery panko topping, Yukon gold potatoes, comfort food side dish