Vegetarian Breakfast Casserole with Brassicas


An easy vegetarian breakfast casserole combines quinoa, cheese, broccoli, kale and rutabaga for a hearty gluten-free breakfast. Perfect for weekend brunch.

Overhead shot of vegetarian breakfast casserole.

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Lazy Saturday mornings are the best. I usually wake up naturally, without an alarm. Then I make a big pot of coffee and figure out what easy, hearty breakfast I can make.

This vegetarian breakfast casserole is one of my favorites for weekend brunch. It changes with the season, depending on what vegetables are available. And varies with what grains are leftover in my fridge. Nevertheless, it’s always delicious.

Cross section of the breakfast casserole

Vegetarian Breakfast Casserole with Brassicas

One of the reasons I love this recipe is because it’s less of a recipe, and more of a reference. A recipe sketch as Mark Bittman calls it in Kitchen Express (<-affiliate). It’s a recipe template, cooked by ratios.

What exactly does that mean?

While you can follow this recipe exactly, you don’t have to. You can swap out the grains. Any leftover grain will do. Brown rice, spelt, farro, kamut. Or omit the grains entirely and serve a vegetarian frittata or a breakfast egg bake.

Ingredients for a vegetarian breakfast casserole

Cheese is also negotiable. Cheddar is an excellent choice. Or try something stronger like fontina or smoked gouda. Depending on your vegetables, you may even use dill havarti.

This time of the year, I usually make this vegetarian breakfast casserole with winter brassicas. But if it’s summer, bell peppers and tomatoes are prime candidates. In fall, roasted sweet potatoes, delicata squash, or butternut squash are the featured vegetables.

No matter what ingredients I use, I usually end up with the following ratio: 1 part egg mixture : 3 parts vegetables : 1 part grain. This is the ideal ratio for me since I love having lots of vegetables in my savory breakfasts. You can fine tune your ratio based on your preference.

Unbaked breakfast casserole.

Using Brassica Vegetables

Brassica vegetables belong to the plant family Brassicaceae, also known as the mustard, crucifer, or cabbage family. Some of the most common (and uncommon) vegetables include:

  • Broccoli
  • Kale
  • Cabbage
  • Cauliflower
  • Turnip
  • Rutabaga
  • Brussels sprouts
  • Kohrabi
  • Horesradish
  • Arugula
  • Collard greens

In fact, broccoli, kale, cabbage, collard greens, cauliflower, brussels sprouts and kohlrabi are all the same species (Brassica oleracea). They’re just different varieties that have been grown to specialize in the edibility of one plant part.

FLOWER: Broccoli florets and cauliflower are actually the flower part of the plant. Leave the crown attached to the plant and you’ll often get flowers with yellow or white blossoms.

LEAF: Kale, arugula, cabbage, Brussels sprouts and collard greens are some of the most common leaf vegetables of the brassicas. Turnip leaves are also edible, and a nutritious (though often wasted) ingredient.

ROOT: Rutabagas have a starchier texture compared with other brassicas. I like the heft and the bulk they add to this vegetarian breakfast casserole. Turnips and radishes are other root vegetables in this plant family.

STEM: The stalks of broccoli are definitely edible and this breakfast casserole is a great way to use them. Kohlrabi is grown specifically for to eat the stalk part of the plant.

There’s so much edible variety within this plant family, I chose to use different parts of the plants in this vegetarian breakfast casserole. This breakfast bake is meant to be played with.

And I’d love to hear about your variations in the comments below!

Serving vegetarian breakfast casserole

An easy vegetarian breakfast casserole combines quinoa, cheese, broccoli, kale and rutabaga for a hearty gluten-free breakfast. Perfect for a healthy weekend brunch. #breakfast #vegetarian #vegetarianrecipe #breakfastrecipe #glutenfree #quinoa #broccoli #kale #rutabaga

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5 from 1 vote

Vegetarian breakfast casserole with Brassicas

An easy vegetarian breakfast casserole combines quinoa, cheese, broccoli, kale and rutabaga for a hearty gluten-free breakfast. Perfect for weekend brunch.

Prep Time 10 minutes
Cook Time 1 hour
Total Time 1 hour 10 minutes
Servings 6 servings
Calories 326 kcal


  • 1 tablespoon olive oil
  • 1 small head broccoli diced (about 1/2 pound)
  • 1 small bunch kale thinly sliced (about 1/2 pound)
  • 2 small rutabaga diced (about 1/2 pound)
  • 1/2 tablespoon garlic powder
  • 2 cups cooked quinoa
  • 6 egg
  • 1/2 cup milk
  • 6 ounces shredded cheddar


  1. Heat oven to 375°F.
  2. While oven is heating, warm olive oil over medium heat in a large pan. Add broccoli, kale, and rutabaga. Sprinkle garlic powder and salt and pepper to taste. Stir and cook about 5 minutes. The broccoli should still be bright green and the kale, slightly wilted. Mix in cooked quinoa. Remove from heat and let cool slightly.
  3. Whisk together eggs and milk in a small bowl.
  4. Transfer vegetables and quinoa into a large baking dish. Pour egg and milk mixture into the baking dish. Stir together to combine and mix in half the cheese.
  5. Top with the remaining cheese, cover with foil and bake for 30 minutes.
  6. Remove foil and bake vegetarian breakfast casserole for 10 to 15 minutes more until the cheese is lightly browned and the casserole set.
  7. Serve immediately.

Recipe Notes

Seasoned Secret

Covering the breakfast casserole helps it cook evenly and prevents the top from burning. Removing the foil and baking an additional 10 to 15 minutes allows the top to crisp.

I used a relatively deep baking dish from Crate and Barrel. The enamel coating makes it easy to clean and the depth is also good for lasagna and baked pastas.

If you’re looking to do more “off recipe” cooking, I highly recommend Salt, Fat, Acid, Heat (<-affiliate) and Ruhlman’s Twenty (<-affiliate).


Be sure to use a gluten free grain like quinoa or rice. Or omit the grains entirely.


Add traditional breakfast meats such as cooked bacon, ham or sausage. Or try nontraditional breakfast options like steak, shredded chicken, or pulled pork.

Check the Fridge

Anything goes! Whatever vegetables need to be used are fair game in this vegetarian breakfast casserole.

Single serving of breakfast casserole

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  • Reply
    Bekah K
    March 18, 2018 at 10:25 am

    I used asparagus, green peppers, and collard greens instead of kale and broccoli, and it is so good! I also cut the recipe by more than half and used a bread loaf pan because I’m only cooking for two. Next time, I think I’ll make it a little spicier, but that’s my preference. This was an easy and delicious breakfast!

    • Reply
      March 20, 2018 at 4:39 pm

      What a great use of other vegetables and good idea on the loaf pan when cutting the recipe in half!

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