Cheesy Chicken Spaghetti Squash Casserole

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
• Italian Seasoning
• Salt
• Green Bell Pepper, diced
• Diced Tomatoes (drained, about 2/3 cup)
• Cream of Mushroom
• Plain Greek Yogurt
• Minced Garlic
• Shredded Cheese (divided)
• Chopped Fresh Basil or Chives (optional)

TIP: I order my chicken from Butcher Box! 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:

1. 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.
2. Prep the Filling: While the squash and chicken bake, chop the other veggies and prep the creamy sauce ingredients.
3. 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!
4. 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 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 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