This Cheesy Rosemary Mashed Potato Casserole may be the best mash you’ll ever eat. This side everything you want from your favorite side dish, creamy, cheesy, full of rosemary flavor with a crispy topping. The best make ahead holiday side dish.

A spoonful of cheesy rosemary mashed potatoes

This is recipe #3 in this weeks complete holiday dinner series. In case you missed them, I’ve already published slow cooker green beans with shallots and almonds and the star of the table, herb roasted beef tenderloin.

I don’t really know where to start talking about this casserole. I do know I ate too much of it before I sat down for my meal and I do know that any holiday dinner. Whether it’s Thanksgiving or Christmas, really good mash is mandatory.

Mashed potato in a casserole dish topped with crispy panko breadcrumbs

A great make ahead dish

This Cheesy Rosemary Mashed Potato Casserole is the perfect dish to take some help from prepping ahead. You can make this a couple of days before your holiday dinner. Make up to the point of baking but don’t add the panko and Parmesan. Cover and refrigerate until ready to bake, add the toppings then as directed in the recipe. How easy was that?

Mash until your arm hurts for no lumps

The key to really soft and creamy mash is first, you have to mash really well. If there are any lumps, well, no mash really should have lumps. I live by my ricer for mashed potatoes. if you haven’t seen a ricer, it’s like a giant garlic press. You can see it in the video below.

Here are the other recipes for the complete holiday dinner that you can see in the picture above:

If you’ve made this, or any other recipe, leave a comment below. I love to hear from my readers and feedback is very important.

Yield: 8

Cheesy Rosemary Mashed Potato Casserole

Creamy mashed potatoes topped with panko on a spoon

Mashed potato with fresh rosemary and cheese is soft and creamy. Topped with breadcrumbs and Parmesan then baked.

Prep Time 10 minutes
Cook Time 45 minutes
Total Time 55 minutes


  • 5 pounds (2.2) potatoes of your choice, peeled and quartered
  • 2 tablespoons salt
  • 2 cups (473 ml) heavy cream, warm
  • 1/2 cup (113 grams) unsalted butter, melted
  • 1 cup (83 grams) white cheddar cheese, grated
  • 1 cup (83 grams) mozzarella cheese, grated
  • 2 tablespoons fresh rosemary, chopped
  • 1/2 teaspoon ground black pepper
  • 1 cup (108 grams) panko breadcrumbs
  • 1 cup (83 grams) Parmesan cheese, grated


  1. Add the potatoes to a large pan and cover with water. Bring to a boil, add the 2 tablespoons salt and simmer for 15 minutes until tender. Drain and add to a large bowl.
  2. Preheat oven to 375°F/190°C. Butter the inside of a 9 x 13-inch (23 x 33 cm) casserole dish.
  3. Run the potatoes through a ricer or food mill or mash really well to get the smoothest mash possible
  4. Add the cream, butter, cheeses, rosemary and pepper. Stir until combined and the cheese is melted. Taste and add salt if needed.
  5. Pour the mash into the casserole dish and spread evenly. Mix the breadcrumbs and Parmesan in a bowl. Sprinkle an even layer of breadcrumbs and Parmesan cheese on top of the mashed potato.
  6. Bake for 30 minutes until the top is golden.

Nutrition Information



Serving Size


Amount Per Serving Calories 750Saturated Fat 32gCholesterol 172mgSodium 2505mgCarbohydrates 43gProtein 27g