Healthy Broccoli Casserole

Healthy Broccoli Casserole with a creamy cheddar cheese sauce, mushrooms, and crispy onions will be your new favorite holiday casserole. Plus you can prep it ahead of time! Jump to Recipe

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This delicious holiday casserole is a mash-up of broccoli and green bean casserole that you will immediately love. Tender crisp broccoli tossed in a delicious mushroom gravy topped with cheddar cheese and crispy onions. It will fly off your holiday table and no one will ever believe this tasty broccoli casserole is actually healthy.

Growing up my Mom made this amazing broccoli casserole that was basically a combination of frozen chopped broccoli, cheddar cheese, mayonnaise, and cream of mushroom soup all covered in breadcrumbs. It was surprisingly delicious (give that ingredient list) but obviously isn't the healthiest of the freshest recipe. I knew this holiday season, I wanted to create a healthier version of this dish.

While I normally would start from scratch to create this recipe, this year I wanted to start with my absolute favorite Healthy Green Bean Casserole from Gimme Some Oven. I have been making this recipe for the past year and it is seriously the best lightened up casserole recipe. However, I wanted to change a few things to incorporate the cheddar cheese that is typically found in broccoli casserole.

Let's talk about what makes this recipe so delicious. First, it starts with fresh broccoli instead of frozen. This ensures that your broccoli will have some crunch and texture. Frozen broccoli tends to get mushy. That is tossed with a creamy cheddar cheese sauce packed with mushrooms and plenty of garlic. Finally, everything is finished with another layer of cheddar cheese and tons of crispy red onions. So so good.

Broccoli casserole with crispy red onion, breadcrumbs, and mushrooms in a ceramic dish.

Recipe Ideas

There are lots of ways to make this broccoli casserole unique and exactly what your family will love.

  • Try a different cheese: Although I can't get enough cheddar cheese and broccoli, this will also work great with Parmesan cheese, pepper jack (for something spicy), Swiss, or any other cheese that melts well. You can also use a combination of cheeses. Basically, anything that would work in macaroni and cheese will work well here.
  • Add herbs or spices: Fresh herbs are a great addition to this dish. Dried herbs work great as well. Consider adding some thyme, rosemary, or Italian seasoning. You could also add some heat with red pepper flakes, smokiness with cumin, or extra flavor with onion or garlic powder. I find this works best when you add the herbs and spices to the mushroom sauce.
  • Use a different vegetable: If you aren't feeling the broccoli, you can make this with cauliflower, green beans, or even butternut squash. Just make sure to par-cook any vegetable you use. 
  • Make it gluten-free: Just substitute a GF flour and breadcrumbs.
  • Without onions: If you aren't a huge onion person, just leave them out. Top the casserole with a layer of cheddar cheese and toasted breadcrumbs. 

How to Make in Advance

Broccoli casserole is a dish that can be prepped the day before to make holiday meal prep easier. Simply assemble the casserole and cover it with foil or plastic wrap and store it in the fridge. If possible, remove it from the oven 30-45 minutes before cooking to remove the chill. If not, just add 5-10 minutes to the baking time. 

Can I freeze broccoli casserole?

Personally I don't recommend freezing this type of casserole because the broccoli and onion topping will get mushy. The sauce can also separate when you are reheating it. This is best eaten right after cooking and leftovers can be stored in the fridge for 3-4 days. Reheat in the microwave, a saute pan, or in the oven.

Can I use frozen broccoli?

Frozen broccoli can be used in place of fresh but the texture will be slightly different and a bit mushy. Start by cooking the frozen broccoli until just cooked. Immediately run it under cold water to stop the cooking. Dry it well to ensure your casserole isn't watery. Then use it as you would the fresh.

Can I add rice or pasta? What about Chicken?

To turn this into a main course, you can add some cooked rice or pasta. If you plan on doing this, make sure to double or triple the mushroom sauce. Then simply fold the cooked pasta (cooked until al dente) or cooked rice in with the broccoli. If you like, you can also add some cooked chicken as well.

Healthier casserole with broccoli, mushrooms, cheddar cheese, and crispy onions.

What to Serve with Broccoli Casserole

It should go without saying, that this is the perfect dish for Thanksgiving or any holiday serving. It goes great with turkey, ham, or any other holiday proteins. We also love pairing it with a simple store-bought rotisserie chicken or roasted chicken with cauliflower mashed potatoes and cranberry sauce. It feels like a holiday meal but is easy enough for a weeknight.

Looking for more broccoli recipes?

The Recipe
Healthy broccoli casserole with mushrooms, cheddar cheese, and crispy onions in a baking dish with a spoon.

Healthy Broccoli Casserole

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  • 2 lbs broccoli florets
  • 3 tbsp butter, divided
  • 1 U red onion, thinly sliced
  • 1/2 cup Panko breadcrumbs
  • 8 oz baby bella mushrooms, sliced
  • 4 U garlic cloves, minced
  • 3 tbsp white whole wheat flour
  • 1/2 cup chicken broth
  • 1 cup 2% milk
  • 1 cup shredded cheddar cheese, divided

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Preheat the oven to 375 degrees.


Bring a large pot of water to a boil. Add the broccoli and cook for 3-4 minutes until bright green and just tender. Add to a colander and toss with ice and cold water to stop them from cooking longer. Dry well.


Make the crispy onion topping. Melt 1/2 tbsp of butter in a pan over medium high heat. Add the onions and cook for 4-5 minutes until tender but still have thier shape. Remove the set aside in a bowl. Add another 1/2 tbsp of butter. Add the breadcrumbs and cook for 2-3 minutes until golden brown. Toss with the onions.


Make the mushroom sauce. Melt two tablespoons of butter in a pan. Add the mushrooms and cook for 4-5 minutes until tender. Stir in the garlic and cook for 1-2 minutes until fragrant. Stir in the flour and cook for about 1 minute until light brown. Add the chicken broth and stir until the flour dissolves into the broth. Add the milk and 1/2 cup cheddar cheese. Bring to a simmer and cook for 3-5 minutes until it thickens. Season well with salt and pepper.


Spray a 9 X 13 dish with cooking spray. Add the broccoli florets and pour the mushroom sauce on top. Stir together so the broccoli is coated in the sauce. Top with 1/2 cup of shredded cheddar cheese. Then add the crispy onions.


Bake for 20-25 minutes until casserole is bubbling and the onions are crispy and golden brown. If needed, you can broil for 1-2 minutes to brown the top more.

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Nutritional Facts
Serving Size: 1/2-2/3 cup
Amount Per Serving
Calories 129
Calories from Fat 64
% Daily Value *
Total Fat 7g
Saturated Fat 4g
Monounsaturated Fat 0g
Polyunsaturated Fat 0g
Cholesterol 21mg
Sodium 111mg
Total Carbohydrate 12g
Dietary Fiber 2g
Sugars 3g
Protein 7g

* Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

The Nutritional Values provided are estimates only and may vary based on the preparation method.

† SmartPoints™ calculated by Slender Kitchen; Not endorsed by Weight Watchers International, Inc.
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About the author Meet Kristen Mccaffrey
Hi, I’m the cookbook author, recipe developer, and food enthusiast behind Slender Kitchen. I am obsessed with making healthy food that is easy to prepare and absolutely delicious. Meal planning is my secret weapon and I hope I can make meal time easier for you with our tired and tested recipes and foolproof meal plans. Learn More
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