Creamy Spinach Casserole

This creamy spinach casserole with a homemade sauce is a classic side dish that is popular with any and all spinach lovers!

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Spinach casserole is a classic side dish that is popular with any and all spinach lovers! The classic recipe uses mushroom soup, (which hey, I love!) but I wanted to make this one with a sauce completely from scratch.

For another great way to get some spinach in your diet, why not try my Pan Fried Spinach & Cream Cheese Stuffed Chicken Breasts, or my Creamed Spinach? Or for another great casserole dish, how about a Broccoli Rice Casserole?

Creamy Spinach Casserole

Spinach Casserole

This recipe uses an absolute ton of spinach in a creamy mornay sauce to make a cheesy, thick, and luscious casserole. Topped with some crumbly Panko breadcrumbs, you could serve this as a side dish or just eat it for dinner all on its own.

It can seem impossible to fit enough vegetables into your daily diet. So, why not cheat? Here is a delicious spinach casserole dish that gets you all of the iron you need while still tasting great!

spinach casserole ingredients

Ingredients for Spinach Casserole


  • Frozen Spinach (a LOT of it!)
  • Butter
  • Onion
  • Garlic
  • Flour
  • Nutmeg & Cayenne pepper
  • Milk
  • Heavy Cream
  • Cream Cheese
  • Parmesan
  • Swiss or Gruyere cheese (anything pungent and strong would work here)

Buttery Panko Topping

  • Panko breadcrumbs – You can use any breadcrumbs here (or even toast your own!), but Panko breadcrumbs really shine here. Their craggily, irregular shape makes them crisp up incredibly well.
  • Butter
  • Parmesan
wooden spoon full of spinach casserole

How to Make Spinach Casserole

  • Thaw your spinach out and drain it of any excess water.
  • Sauté your onions in a saucepan with butter over medium heat until soft and translucent.
  • Add garlic and cook until fragrant
  • Add in your flour, stirring until the whole mixture is brown and smells like a cooked pie crust
  • Add your nutmeg and then pour in half your milk slowly, constantly whisking to make a roux. Once fully incorporated, add the rest of your milk and the cream.
  • Stir in all your different cheeses until they are totally melted in, followed by the spinach.
  • Season to taste and pour into a 9×13 pan.
  • Mix together your Panko topping ingredients and sprinkle liberally over your casserole into a single, even layer.
  • Bake at 375 Fahrenheit for 25 minutes, or until bubbling.


How to Freeze Spinach Casserole

Freezing leftover dishes with a lot of cheese and milk often seems impossible, but it actually isn’t too hard if you do it right.

The key is to wait until your casserole has completely cooled down before you portion it up and freeze it individually wrapped. Storing it in freezer-safe containers individually means that you can take out only as many casserole portions that you need.

close up of spinach casserole

How to Cook Spinach Casserole from Frozen

While you could just eat a defrosted piece of spinach casserole cold, it is a lot better when it is heated up. However, since this spinach casserole is primarily made from dairy, you will probably struggle to reheat it using the microwave.

If you tried zapping it in the microwave, you would probably end up with a gloopy, separated sauce with bits of cheese fat pooling around it.

Instead, try heating it up in the oven in a covered baking dish at 350 Fahrenheit for about 30 minutes. By keeping it covered from the direct heat, excess water will help steam the casserole, reheating it without separating the sauce.

How to Squeeze out Frozen Spinach

Since you are using a huge amount of spinach in this dish, it makes sense to get it frozen. While you could get some fresh spinach and use it instead, you’d have to par-cook it in numerous batches to wilt it down, so frozen is a lot easier.

Just make sure that you thoroughly drain away all of the water from your frozen spinach when it is defrosted. It normally wouldn’t matter, but the huge amount of water coming from the spinach would thin out the sauce if you didn’t get rid of it.

To remove the water, squeeze your defrosted spinach tightly in your hands while over the sink. It will all clump together into a big ball, but don’t worry; it will separate again when you add it to the sauce.

Happy cooking!



Creamy Spinach Casserole

This creamy spinach casserole with a homemade sauce is a classic side dish that is popular with any and all spinach lovers!
5 from 13 votes
Prep Time
30 minutes
Cook Time
25 minutes
Side Dish
Karlynn Johnston


  • four 10-ounce packages of frozen spinach defrosted and excess moisture squeezed out
  • 1/4 cup salted butter
  • 1 large onion diced
  • 1 tablespoon minced garlic
  • 1/4 cup flour
  • 1/4 teaspoon grated nutmeg
  • 1/8 teaspoon cayenne pepper
  • 2 cups milk
  • 1/2 cup heavy cream
  • 1/4 cup cream cheese softened and at room temperature
  • 1/4 cup freshly grated Parmesan
  • 1 cup grated Swiss or Gruyere cheese
  • salt and black pepper to taste

Buttery Panko Topping

  • 1 1/2 cups panko crumbs
  • 1/4 cup salted butter melted
  • 1/2 cup freshly grated Parmesan cheese


  • Preheat your oven to 375° F. Grease a 9×13 pan with butter and set aside.
  • Prepare your spinach and set aside on paper towels to help it drain even more while you prepare the cheese sauce. This takes a lot of time, make sure to do this now before you start the sauce!
  • Melt the butter in a large, heavy bottomed saucepan over medium heat. Add in the onions and sauté until they are soft and translucent, about 15 minutes.
  • Add the garlic and sauté until browned and fragrant, about 2 more minutes.
  • Add in the flour and cook, stirring constantly, until browned, around 2-3 minutes. (This adds flavor to the roux.) Add in the nutmeg and mix in.
  • Pour in one cup of the milk slowly, whisking the mixture to ensure that there are no lumps. Once you have added it and the mixture is smooth and creamy, you can add the remaining milk and the cream, whisking constantly to keep it smooth.
  • Stir in the cream cheese, Parmesan, and gruyere cheese, and keep stirring until they have melted in.
  • Stir in the spinach.
  • Season now with salt and pepper to taste.
  • Spoon the spinach filling into the prepared 9×13 pan.
  • In a small bowl, combine the topping ingredients until mixed together completely.
  • Sprinkle over the casserole in an even layer.
  • Bake in the preheated oven for 25-30 minutes until hot and bubbly. Cover the top with aluminum foil if the topping starts to brown too quickly.
  • Remove and let stand for 5 minutes before serving.

Recipe Notes

  • You can adjust the topping to your liking, adding some spices if you like!

Nutrition Information

Calories: 310kcal, Carbohydrates: 14g, Protein: 11g, Fat: 24g, Saturated Fat: 14g, Cholesterol: 71mg, Sodium: 356mg, Potassium: 136mg, Fiber: 1g, Sugar: 4g, Vitamin A: 808IU, Vitamin C: 1mg, Calcium: 315mg, Iron: 1mg

All calories and info are based on a third party calculator and are only an estimate. Actual nutritional info will vary with brands used, your measuring methods, portion sizes and more.

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Karlynn Johnston

I’m a busy mom of two, wife & cookbook author who loves creating fast, fresh meals for my little family on the Canadian prairies. Karlynn Facts: I'm allergic to broccoli. I've never met a cocktail that I didn't like. I would rather burn down my house than clean it. Most of all, I love helping YOU get dinner ready because there's nothing more important than connecting with our loved ones around the dinner table!

Learn more about me

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Comments & Recipe Tips Share a tip or comment!

  1. Laura Wood says

    Can I cut the recipe in half and use an 8×8 baking dish?

  2. Eleanor says

    Best way to squeeze water out of frozen thawed spinach is to use a potato ricer!

5 from 13 votes (13 ratings without comment)

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