Spinach Gratin (Spinach Casserole)

Prep Time 10 minutes
Cook Time 40 minutes
Total Time 50 minutes
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Spinach Gratin is a wonderful creamy, and cheesy, side dish that looks and tastes fancy, but is easy to make and can be prepped ahead! Filled with robust gruyere cheese and a pinch of nutmeg, this recipe for spinach casserole takes this classic steakhouse side dish to the next level!

A bowl with a serving of spinach casserole and two toasts.

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Creamy And Cheesy Spinach Casserole

Warm, cozy, casserole-style sides are always a win, aren’t they? And this cheesy Spinach Gratin definitely hits all of the right notes! This easy and cheesy spinach casserole starts with easy frozen chopped spinach that is cooked and folded into a decadent, creamy and cheesy sauce. Transfer the creamy spinach to a casserole dish, top it with a thick layer of Gruyere cheese, and bake until bubbly.

No matter if it’s a holiday, or a just a regular weeknight, this cheesy spinach casserole will be a hit with everyone. Even my kiddo who doesn’t love vegetables gobbles this one up. The rich, savory flavor and all that cheese is seriously addictive, I bet you won’t have leftovers!

Bonus points: this side dish is gluten free and low carb! Looking for more easy low carb side dishes? Check out my favorite Mashed Cauliflower, this Green Bean Salad, or these delicious Sautéed Green Beans with Bacon!

Ingredients in bowls with salt and pepper shakers.

What You Will Need

You will only need a handful of ingredients to make these delectable spinach casserole!

  • Frozen Chopped Spinach: Frozen chopped spinach is a lot easier, and more efficient, to use in a recipe like this. If you prefer, you can sauté fresh spinach, you will need to cook and squeeze the liquid out of it. You will need 30 oz cooked spinach.
  • Butter: I love using my favorite Challenge Unsalted Butter
  • Yellow Onion: You can also use white, but I like the slight sweetness that a sweeter yellow onion adds.
  • Garlic: Freshly minced garlic will add the most flavor!
  • Cream Cheese: This gives your spinach a perfect creamy texture. I like to use the full fat cream cheese for best texture and overall flavor.
  • Shredded Gruyere Cheese: If you do not have gruyere, you can also use mozzarella or gouda.
  • Shredded Parmesan Cheese: You can use parmesan, pecorino or asiago.
  • Freshly Grated Nutmeg: This is an optional ingredient, but adds a ton of depth! Just a little elevates this dish so much. Freshly grating the nutmeg does make a big difference, I use whole nutmegs and a fine grater!
  • Salt and Pepper: Freshly cracked pepper and salt, to taste!

I ❤️ CHALLENGE BUTTER!

If you open my fridge, Challenge Butter is the only butter you are going to find. Challenge Butter is made the old-fashioned way with the freshest milk and cream from happy cows. It is 100% natural and doesn’t have any artificial preservatives, fillers, dyes or added hormones.

I always use Challenge Butter in my kitchen because it is churned fresh daily, as it always has been since the company began in 1911! Challenge Butter is also farmer-owned with more than 450 family-owned dairies. I love knowing that we are helping to support other families!

Cooked spinach in a tea towel in a bowl.

How To Make Spinach Gratin

  • Prep. Preheat oven to 425°F. Grease a 9×11 inch baking dish with non-stick spray.
  • Cook Spinach. Cook the frozen chopped spinach in the microwave according to package directions. Remove excess water (squeeze carefully using a cheese cloth, tea towel, or a fine mesh sieve) and set aside.
  • Sauté. In a large skillet over medium high heat, melt the butter. Add onion and sauté until translucent. Add garlic and cook for 30 seconds. 
  • Cream. Add cream cheese and cook, stirring, until melted. Add heavy cream and cook for 2 minutes. Add gruyere cheese and parmesan cheese stirring till well combined.
Creamed spinach in a baking dish with shredded cheese on top.
  • Fold. Fold in spinach into the cream sauce and season with nutmeg, salt, and pepper, to taste. 
  • Bake. Transfer spinach to prepared baking dish and top with remaining 1 cup shredded gruyere cheese. Bake for 15 to 20 minutes, until cheese is melted and edges are bubbling. 
Spinach casserole in a baking dish with a tea towel and toasts.

Tips For Best Success

  • Frozen Spinach. I highly recommend using frozen spinach in this recipe over fresh spinach. You will need to steam a lot of fresh spinach to get enough spinach for this recipe. If you choose to use fresh spinach, you will need to steam/wilt the spinach and then squeeze out any excess water. You will need 30 oz spinach (weigh it after you have squeezed out the water).
  • Squeeze Out The Water. It’s super important to make sure to squeeze out all the excess water out of your spinach that you can. If you leave too much liquid in the spinach, it will make your gratin soupy. I like to use cheese cloth, a tea towel, or a fine mesh sieve (just press it in your sieve with a spatula to remove the excess liquid).
  • Nutmeg. Nutmeg may be a little surprising if this is your first time making a dish like this, but a little nutmeg added to a creamy dish with greens in it (think Creamed Spinach, Homemade Green Bean Casserole, Cheesy Creamed Green Beans, etc) is very common and adds a delicious depth of flavor. It’s just a pinch, no one will know what you actually added, but it really elevates your dish to the next level! Freshly grating a whole nutmeg with a fine grater is truly the best!
A spoon scooping up a serving of spinach casserole.

Frequently Asked Questions

Can I add breadcrumbs to the top?

As this recipe is below, it is gluten free and low carb, however if you want to, you can add 3/4 cup panko bread crumbs on top of the cheese before baking to give your spinach casserole a deliciously crispy topping!

Can I make a roux instead?

If you prefer to make a roux and thicken your spinach mixture that way, remove the cream cheese (used as a thickener) and add 1/4 cup all purpose flour to your skillet once the onions are translucent. Sauté the flour and onion mixture for a minute before continuing on with the recipe. If it happens to get too thick, you can add a little broth to thin it out again.

Can I use a different kind of cheese?

I highly recommend using the parmesan (or asiago or pecorino cheese), but you can change up the Gruyere cheese to something more commonly found or budget friendly. Gruyere can be swapped for shredded mozzarella, gouda, or even provolone.

Can I prep this ahead?

Absolutely! This is a great make ahead side dish. Follow all the steps up until the baking step. Instead of baking the gratin, wrap it tightly with Saran Wrap or foil and refrigerate it for up to 48 hours. Remove the casserole 1 hour before baking and let it sit on the counter at room temperature. Then bake according to recipe directions!

SERVING IDEAS

I would usually serve a dish like this as part of a holiday spread or family feast. You can also serve as an easy weeknight meal with…

  • Chicken: One of our hands-down favorite dinners is this easy Best Baked Chicken. It’s loaded with flavor, and goes with everything.
  • Salmon Patties: There’s just something about Crispy Salmon Patties and creamy spinach – a savory, healthy combo that is familiar and yet different from a routine meal.
  • Ham: Get that extra ham you bought when they were on sale out of the freezer, and let it become the basis for a few hearty meals! This Crockpot Ham recipe is a great, hands-off way to cook a ham. Or if you are looking to impress your guests, this epic Orange Glazed Ham is a show stopper!
  • Turkey: And of course, if it’s the holidays, these creamed green beans go perfectly with a gorgeous Thanksgiving Turkey!
  • Beef: If you are looking for an amazing holiday dinner, pair this creamy spinach casserole with these Red Wine Braised Short Ribs for an insanely decadent dinner. Don’t forget the Garlic Mashed Potatoes to finish out your meal!
Spinach gratin with cheese and fresh herbs on top.

Storage:

Leftovers: Store any leftover spinach casserole in an airtight container in the fridge for up to 5 days. Bake or microwave until heated through.

Freezer Friendly: Freeze in an airtight container for up to 3 months. I like to use freezer friendly ziplock bags. To thaw, you can go straight from the freezer into the microwave. Use a microwave safe bowl with an added tablespoon of water, heat in 60 second intervals, and stir often. Or, you can also remove it from the freezer and place it in the fridge to thaw 24 hours before. Then reheat on stove top or microwave! 

Make Ahead

Prep Ahead: Follow all the steps up until the baking step. Instead of baking the gratin, wrap it tightly with Saran Wrap or foil and refrigerate it for up to 48 hours. Remove the casserole 1 hour before baking and let it sit on the counter at room temperature. Then bake according to recipe directions!

Freeze Unbaked Casserole: If you want to prep and freeze this spinach gratin ahead, you absolutely can! Prep casserole, but do not bake. Allow to cool completely. Then wrap tightly (I like to do a layer of Saran Wrap and then a layer of foil) and freeze for up to 6 months. Transfer casserole to the fridge 24 hours before you want to serve it to allow it to thaw. Then an hour before baking, remove casserole from the fridge and let it sit at room temperature. Bake according to recipe directions.

A baking dish filled with cheesy spinach casserole on a cutting board with a tea towel.
A spoon scooping up a serving of spinach casserole.
4.6 from 10 votes
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Yield: 8 servings

Spinach Gratin (Spinach Casserole)

Spinach Gratin is a wonderful creamy, and cheesy, side dish that looks and tastes fancy, but is easy to make and can be prepped ahead! Filled with robust gruyere cheese and a pinch of nutmeg, this recipe for spinach casserole takes this classic steakhouse side dish to the next level!
Prep Time10 minutes
Cook Time40 minutes
Total Time50 minutes

Ingredients

  • 3 10 oz bags frozen chopped spinach
  • 3 tablespoons salted Challenge Butter
  • 1 medium yellow onion, diced
  • 6 large cloves garlic, minced
  • 4 oz cream cheese
  • 1 cup heavy cream
  • 2 cups shredded gruyere cheese, divided
  • ½ cup grated parmesan cheese
  • ½ teaspoon freshly grated nutmeg, optional
  • salt and freshly cracked pepper, to taste

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Instructions 

  • Preheat oven to 425°F. Spray a 9×11 inch baking dish with non-stick spray, set aside.
  • Cook spinach in the microwave according to package directions. Remove excess water (squeeze carefully using cheese cloth, a tea towel, or a fine mesh sieve and a spatula) and set aside.
  • In a large skillet over medium high heat, melt the butter. Add onion and sauté until translucent. Add garlic and cook for 30 seconds. 
  • Add cream cheese and cook, stirring, until melted. Add heavy cream and cook for 2 minutes. Add gruyere cheese and parmesan cheese stirring till well combined.
  • Fold in spinach into the cream sauce and then season with nutmeg, salt, and pepper, to taste.
  • Transfer spinach to the prepared baking dish and top with the remaining 1 cup shredded gruyere cheese.
  • Bake for 15 to 20 minutes, until cheese is melted and edges are bubbling. Let rest 5 minutes then serve.

Video

Notes

Storage:
  • Fridge: Store leftovers in an airtight container, in the fridge, for up to 5 days.
  • Freezer: Freeze leftovers in an airtight container for up to 6 months. For best results, let thaw overnight in the fridge before reheating.
Make/Prep Ahead:
  • Follow all the steps up until the baking step. Instead of baking the gratin, wrap it tightly with Saran Wrap or foil and refrigerate it for up to 48 hours.
  • Remove the casserole 1 hour before baking and let it sit on the counter at room temperature. Then bake according to recipe directions!

Nutrition

Serving: 1, Calories: 309kcal, Carbohydrates: 6g, Protein: 13g, Fat: 27g, Saturated Fat: 16g, Polyunsaturated Fat: 9g, Cholesterol: 84mg, Sodium: 456mg, Fiber: 1g, Sugar: 2g

Categories:

More Easy Vegetable Side Dishes

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Jessica
For the past 15 years, Jorge & Jessica have loved getting to share their families' favorite recipes with all of you. They live in Florida with their 3 kids.