Recipe: Cheesy Potato Breakfast Casserole with Cheddar and Sun-Dried Tomatoes

(Image credit: Faith Durand)

I love breakfast casseroles (I wrote a whole book about casseroles and my favorite chapter was breakfast!). But I feel that too few offer vegetarian options that are hearty enough to stand up to the bacon and sausage-laden classic breakfast dishes. Vegetarian breakfast casseroles often go extra-light, with fresh green vegetables or a smattering of herbs in the eggs. Well, not this one. This is a hearty vegetarian breakfast casserole with all the rich, deep flavor you’d usually get from meat, but even better.

(Image credit: Faith Durand)

The flavor boost in this easy dish comes from two things: Hot mustard, and sun-dried tomatoes. Spicy mustard adds a piquant flavor — not easily identifiable, but a strong supporting player in the background. (Don’t worry — this doesn’t taste overwhelmingly of mustard!)

And then there are sun-dried tomatoes, preferably really good ones packed in oil (perhaps with some herbs) to give umami flavor and a little bit of meaty chew here and there. The cheddar is a great flavor in the mix, too. If you’re feeling fancy, throw in a few leaves of rosemary or thyme, but it doesn’t need it.

This casserole is truly hearty; it’s packed with more potatoes than I usually put in a casserole of this size. But the texture is still light and even fluffy, thanks to the shredded potatoes, which don’t weigh this down like cubed potatoes can.

It’s a great make-ahead breakfast — make a pan of this and take a wedge with you to the office every morning for a few days.

Tester’s Note

The unique thing about this vegetarian breakfast casserole is the spicy mustard, which adds a nice depth of flavor but doesn’t make it actually spicy. I used Gulden’s Spicy Brown Mustard, which is easy to find in most grocery stores. I loved that I was able to assemble this the night before and just pop it into the oven the next morning. Loaded with sautéed onions and garlic, there’s a bit of pep from the sun-dried tomatoes and enough potatoes to make this a hearty and satisfying breakfast.

Christine, December 2018

(Image credit: Apartment Therapy)
78 Ratings

Cheesy Potato Breakfast Casserole with Cheddar & Sun-Dried Tomatoes

Serves8 to 10


  • Cooking spray or olive oil

  • 1 tablespoon

    unsalted butter

  • 1

    small yellow onion, diced

  • 6 cloves

    garlic, minced

  • 2/3 cup

    sun-dried tomatoes, preferably oil-packed, sliced into thin strips

  • 9

    large eggs

  • 3 tablespoons

    spicy brown mustard

  • 1 cup

    whole milk

  • 2 teaspoons

    kosher salt

  • 1/4 teaspoon

    freshly ground black pepper

  • 2 cups

    shredded sharp cheddar cheese

  • 1 pound

    shredded frozen potatoes (about 6 cups, do not thaw)



  1. Arrange a rack in the middle of the oven and heat to 350°F. Lightly coat a 9x13-inch baking dish with cooking spray or olive oil.

  2. Heat the butter in a large skillet over medium heat until it melts and foams up. Add the onion and garlic and cook until the onion has started to soften, about 5 minutes. Add the sun-dried tomatoes and cook until fragrant and the onion is nearly translucent and beginning to brown around the edges, about 5 minutes. Remove from the heat.

  3. Place the eggs and mustard in a large bowl and whisk to combine. Whisk in the milk, salt, and pepper. Fold in the cheddar cheese, frozen potatoes, and sun-dried tomato mixture. Transfer the mixture to the baking dish.

  4. Bake until the eggs are set and the top is slightly golden-brown, 35 to 45 minutes. Serve immediately with a fresh salad or fruit.

Recipe Notes

Make ahead: The casserole can be assembled, covered with plastic wrap, and refrigerated for up to 1 day before baking. It will need about 10 minutes additional baking time.

Storage: Leftovers can be refrigerated in an airtight container for up to 5 days.

(Image credit: Apartment Therapy)