Rosemary and Mushroom Hashbrown Casserole

This is pretty much the ultimate what-to-make-for-Christmas-morning other than cinnamon rolls. This is the savory option. I love hashbrowns in any form, really, but this rosemary and mushroom hashbrown casserole is SO good! It’s creamy, cheesy, and very flavorful. Rosemary is a very holiday scent to me, so it’s also got that going for it as well. Ha.

Another thing I love about this hashbrown casserole is it’s incredibly easy to make. Once you have cooked the mushrooms and onions, you pretty much dump everything together and bake. Easy!

You could absolutely assemble this the night before so all you have to do in the morning is pop this casserole in the oven and let it fill your house with a delicious rosemary smell while you wait for breakfast.

You could serve this casserole alongside any number of things—bacon, sausage, pancakes, cinnamon rolls, whatever! I love that this casserole is vegetarian-friendly, but if you want to serve it alongside some meat, you do you, friend. 🙂

I’m pretty sure I’ll be eating a version of this Christmas morning this year, but honestly this is a great recipe anytime you may have guests over for breakfast and need an easy crowd-pleasing casserole. Enjoy! xo. Emma

4.5 from 2 votes

Rosemary and Mushroom Hashbrown Casserole

Course Main Course
Cuisine American
Keyword brunch casserole, hash brown casserole
Servings 12


  • 4 ounces baby portobello mushrooms chopped
  • ½ red onion chopped
  • 4 cloves of garlic minced
  • 1 tablespoon olive oil
  • 40 ounces shredded potatoes store-bought or shred your own
  • 4 eggs
  • 8 ounces sour cream
  • 10.5 ounces cream of mushroom soup
  • 6 ounces cheddar cheese shredded
  • 2 tablespoons rosemary chopped
  • salt and pepper


  1. In a small pan, cook the mushrooms, onions, and garlic in the olive oil over medium heat. Season with a little salt and pepper and cook until well browned. Set aside.

  2. In a large mixing bowl, combine the shredded potatoes, mushroom mixture, eggs, sour cream, cream of mushroom soup, 3 ounces cheddar cheese, and 1 tablespoon chopped rosemary. Stir to combine. Spoon into a 9x13-inch baking dish. Top with the remaining cheese and rosemary.

  3. Bake at 375°F for 28-32 minutes until the edges begin to bubble and brown.

Recipe Notes

You can prep this the night before, cover well, and refrigerate overnight. Then bake in the morning before serving.

Credits // Author and Photography: Emma Chapman. Photos edited with A Color Story Desktop actions.
  • 4 stars
    This turned out delicious! I improvised a bit due to what I had on hand. Stirred in some extra sweet raw onion and garlic powder (was short on fresh garlic by 2 cloves)..used 2 eggs instead of 4 …plus didn’t have time to defrost My mountain picked mushrooms (will definitely add next go round)….it turned out great! Thank You for this awesome recipe. Will definitely be making again.

    • They are raw, but they will cook once they’re in the oven 🙂

  • 5 stars
    I am going to crisp up some bacon and mix it into the hash-browns before baking. After it comes out of the oven, I am going to top it off with a dollop of sour cream, some crumbled bacon, and a sprinkle of shredded cheese. OMG! Now, what will everyone else eat? LOL! I am not good at sharing, well, yes, I am, or am I?

  • This sounds SO good, I can smell the rosemary all the way over here! 🙂

  • This looks delightful for dinner! I have 2 of your books,and admire your style. Thank you. Merry Christmas!

  • Yes Please! I have been trying to decide on a potato dish to go with our Christmas breakfast and this just made the list. YUM.

  • Now I’m at a loss of what to make on Christmas – this or cinnamon rolls, like you said? The casserole looks delicious and seems simple to make too!! 😀

    Charmaine Ng | Architecture & Lifestyle Blog

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