Prep: 15 I’ve been making this Cheesy Chicken Spaghetti Squash Casserole recipe for YEARS and it’s still one of my favorites! With 32g of protein and 100+ 5-star reviews, it’s a high-protein low-carb meal that’s comforting, full of cheesy goodness, and everyone loves. Even my kids are obsessed with this one (and they have no idea that the “spaghetti” is a vegetable)! Quickly prep the ingredients, bake the squash and chicken, then throw it all in a casserole dish. This is the EASIEST weeknight dinner or healthy freezer meal!
Chicken Spaghetti Squash Casserole – The BEST Healthy Freezer Meal or Weeknight Dinner!
Right before we had our first baby, I prepped SO many freezer meals in advance. And thank goodness, because those meals got us through those first few tough weeks with a newborn at home! This Chicken Spaghetti Squash Casserole was one of those freezer meals and it was truly one of my favorites. I made several batches and they froze perfectly, then reheated so quickly and easily.
Fast forward to today (and 3 kiddos later), I’ve been making this recipe on repeat for busy weeknight dinners! It’s creamy, savory, cheesy, and hearty, making it the best filling and comforting meal. Even my picky kids love it, and you’d never guess that it’s gluten-free and full of veggies!
Why You’ll Love This Healthy Casserole Recipe
- Low-Carb/High-Protein – With 32g of protein and 17g carbs, this recipe is filling! You can also adjust ingredients to your own nutritional needs.
- Make Ahead (Or Not!) – Make this casserole ahead of time and freeze it for later. It reheats perfectly! But it’s also great for making on busy weeknights as well.
- 15-Minute Prep Time – The ultimate set-it-and-forget-it recipe!
- Secretly Healthy – Most of the ingredients in this meal are vegetables, but you’d never even know! Perfect for picky kiddos who need hidden veggies sometimes (ahem…mine).
- Creamy + Cheesy – The sauce base is cream of mushroom and the whole thing is topped with cheesy goodness for the ultimate comforting casserole.
RELATED: 23 Healthy Casserole Recipes
Ingredients for Spaghetti Squash Casserole
- Spaghetti Squash
- Chicken Breasts (opens in a new tab)
- Italian Seasoning (opens in a new tab)
- Salt
- Green Bell Pepper, diced
- Diced Tomatoes (opens in a new tab) (drained, about 2/3 cup)
- Cream of Mushroom (opens in a new tab)
- Plain Greek Yogurt
- Minced Garlic
- Shredded Cheese (divided)
- Chopped Fresh Basil or Chives (optional)
TIP: I order my chicken from Butcher Box (opens in a new tab)! It’s a great way to ensure you get QUALITY, organic chicken for a great price. I’m obsessed!
How to Make Chicken Spaghetti Squash Casserole
Making this easy healthy casserole is simple and perfect for a cozy dinner! Here’s how to make Chicken Spaghetti Squash Casserole:
- Bake the Squash & Chicken: Cut the spaghetti squash in half and place it cut-side down in a baking pan with some water. Season the chicken breasts and bake them alongside the squash until both are cooked through.
- Prep the Filling: While the squash and chicken bake, chop the other veggies and prep the creamy sauce ingredients.
- Assemble & Bake: Shred the chicken, scoop out the squash, and mix everything in a casserole dish. Top with cheese and bake until bubbly and golden!
- Serve & Enjoy: Let it cool slightly, garnish with fresh herbs if desired, and dig in!
TIP: You can also cook the chicken ahead of time (here’s how to roast a chicken) or buy a rotisserie chicken at the grocery store to save time!
Variations for Baked Squash Casserole
Buffalo Chicken Spaghetti Squash: Add a little kick by mixing in 1/4 cup of buffalo sauce with the Greek yogurt and cream of mushroom soup. For even more heat, top with a sprinkle of crumbled blue cheese before baking!
Vegetarian Spaghetti Squash Casserole: Skip the chicken and double up on the veggies! Try adding mushrooms, spinach, or zucchini for a hearty vegetarian version. Swap the cream of mushroom soup for a creamy béchamel sauce or a plant-based cream to keep it vegetarian-friendly.
Italian Style Spaghetti Squash Casserole: Replace the cream of mushroom soup with marinara sauce and add in some Italian sausage for a savory twist. Use mozzarella and parmesan cheese instead of cheddar to give it a classic Italian flavor.
Cheesy Pesto Chicken Spaghetti Squash: Mix in a couple of tablespoons of pesto with the Greek yogurt for a delicious herby twist. You can also add some sun-dried tomatoes and swap the cheese for mozzarella for a fresh take on the classic casserole.
Other Vegetable Add-Ins:
- Broccoli
- Chopped Asparagus
- Diced Carrots
- Peas
- Brussels Sprouts
- Spinach or Kale
Refrigerating Leftovers
Store any leftover Cheesy Chicken Spaghetti Squash Casserole in an airtight container (opens in a new tab) and keep it in the fridge for up to 3-4 days! It’s best to let the casserole cool completely before storing it. When you’re ready to enjoy it again, just reheat it in the microwave or oven until it’s warmed through and the cheese is all melty again—so good!
How to Freeze Chicken Spaghetti Squash Casserole
Want to turn this into a healthy freezer meal? Simply make the meal according to the instructions below, then let it cool in a large container. Place the container in the fridge (without a lid) for 30 minutes to 1 hour, then add the lid and move the meal to the freezer, then store for up to 3 months!
To reheat, let the meal thaw in the refrigerator the night before and warm it up in the microwave or oven! You can also heat it from frozen, although it takes a bit longer and will require checking and stirring it often as it warms.
>> Grab your FREE EBOOK copy of 6 Healthy Freezer Meals (opens in a new tab) to make 6 freezer meals in one day (with instructions + recipe cards + grocery list)!
Healthy Casserole Recipes
- Butternut Squash Casserole (Savory!)
- Cauliflower Pizza Casserole
- Tuna and Noodle Casserole
- Chili Relleno Casserole Recipe
- Paleo Chicken Mushroom Casserole
- Chicken Fajita Casserole
More Healthy Freezer Meals You’ll Love
- Slow Cooker Pork Chops And Potatoes W/ Apples
- Low-Carb Turkey Swedish Meatballs
- Skinny Creamy Chicken Enchiladas
- Honey Balsamic Chicken & Veggies
- 30-Minute Healthy Sloppy Joes Recipe
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Cheesy Chicken Spaghetti Squash Casserole
Ingredients
- 1 large spaghetti squash
- 2-3 large chicken breasts (opens in a new tab) (about 1.25 pounds)
- 1 Tablespoon Italian seasoning (opens in a new tab)
- 1/2 teaspoon salt
- 1 medium green bell pepper, diced
- 6 ounces diced tomatoes (opens in a new tab) (drained, about 2/3 cup)
- 1 10.5 ounce can cream of mushroom (opens in a new tab)
- 1/4 cup plain Greek yogurt
- 1 teaspoon minced garlic
- 2 cups shredded cheese (divided)
- 2 Tablespoons chopped fresh basil or chives (optional)
Instructions
- Preheat oven to 400 degrees F.
- Cut the spaghetti squash in half lengthwise, then remove the seeds.
- Fill a baking pan with a 1/4″ layer of water and place each spaghetti squash half face down.
- Place the chicken breasts in a large 9×13” casserole dish. Top evenly with seasoning.
- Bake the spaghetti squash and chicken breasts at the same time for 45-50 minutes (or until the spaghetti squash is soft and the chicken breasts are fully cooked).
- While the squash and chicken are baking, prepare the remaining ingredients.
- Once the squash and chicken are done, shred or dice the chicken into small pieces.
- With a fork, remove the “spaghetti” from the squash.
- Combine everything (except for 1/2 cheese and 1/2 fresh herbs) and mix into the casserole dish.
- Top the casserole with the remaining cheese.
- Lower the heat to 350 degrees F and bake for 15-20 minutes, or until everything is hot and the cheese has melted.
- Garnish with fresh herbs and enjoy or freeze for later!
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I had my groceries delivered and they gave me the smallest spaghetti squash I’ve ever seen so I added some broccoli for bulk. I’m sure it changed the taste somewhat but it was still delicious. Thanks for the recipe!
You’re so welcome! Glad you loved it. Also that’s a great pivot! I actually have a spaghetti squash recipe with broccoli in it if you’re looking for another variation! Spaghetti squash alfredo
Super delicious!! Made this for meal prepping and have enjoyed it every single bite of it!!
Thanks, Kelly. I appreciate the review!
Sooo good! Going to try and freeze a couple for my postpartum freezer meals. Should I that before reheating in oven?
It’s amazing as a postpartum freezer meal! I actually did the same thing with this recipe when I had my first. Yes, I would just add the cheese on top and then freeze the entire thing. It’ll be ready to heat up in the oven straight from frozen!
This chicken spaghetti casserole is delicious! So easy to make and the perfect weeknight dinner. Added to my favorites for sure!
Can you use something else for the cream of mushroom soup?
I would try 1/2 cup plain Greek yogurt + 2-4 Tablespoons warm broth, then mix in 1-2 teaspoons of a multipurpose umami mushroom seasoning blend (or just all-purpose blend) and 1 teaspoon minced garlic. I haven’t made it this way, but that would be my first try!