Can I use fresh spinach instead of frozen?

Yes! You'll need about 3 pounds of fresh spinach to equal the amount in this recipe. Blanch it briefly in boiling water, then shock in ice water, drain thoroughly, and chop before proceeding with the recipe. Fresh spinach requires more prep work but offers a slightly brighter flavor.

My gratin turned out watery. What went wrong?

The most common culprit is inadequately drained spinach. Frozen spinach contains a surprising amount of water that must be thoroughly pressed out. Use cheesecloth or a clean kitchen towel to squeeze out every drop, or press repeatedly in a fine-mesh sieve.

Can I make this recipe lighter?

While the full-fat dairy creates the luxurious texture that makes this dish special, you can substitute light cream cheese and half-and-half for the heavy cream. The result won't be quite as rich but will still be delicious. I don't recommend using fat-free products as they won't melt properly.

Is this spinach gratin gluten-free?

Yes! Unlike many gratins that use flour to thicken the sauce, this recipe relies on cream cheese and reduction to create the perfect consistency, making it naturally gluten-free.

Spinach Gratin (Spinach Casserole) Recipe

Name: Spinach Gratin (Spinach Casserole) Recipe
Prep time: 10 min
Cook time: 40 min
Total time: 50 min
Cuisine: American
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

This luxuriously creamy Spinach Gratin transforms humble frozen spinach into a sophisticated side dish that tastes like it belongs in a high-end steakhouse. With its perfect balance of cheesy richness and earthy spinach flavor, this casserole comes together in just 50 minutes, making it ideal for both weeknight dinners and special occasions. The golden, bubbly cheese topping alone will have everyone asking for seconds!

Why You’ll Love This Recipe

Deceptively Simple: Don’t let the elegant result fool you—this gratin requires minimal prep work and uses everyday ingredients.
Make-Ahead Friendly: Prepare everything up to the baking step and refrigerate for up to 48 hours, making it perfect for holiday meal planning.
Crowd-Pleaser: Even spinach skeptics will be won over by the creamy, cheesy goodness of this dish.
Versatile: Works equally well as a hearty side dish or as a vegetarian main course when paired with a simple salad.

Ingredients You’ll Need

Frozen Chopped Spinach: The star of the show! Using frozen spinach saves significant prep time while delivering all the nutritional benefits.
Butter: Creates the flavorful base for your sauce, adding richness and depth.
Yellow Onion: Provides sweetness and aromatic foundation that balances the earthiness of the spinach.
Garlic: Adds essential savory notes that elevate the entire dish.
Cream Cheese: Creates incredible creaminess while adding a subtle tangy note.
Heavy Cream: Brings luxurious richness and helps create the perfect sauce consistency.
Gruyere Cheese: This Swiss cheese delivers both sophisticated flavor and that magnificent stretchy texture when melted.
Parmesan Cheese: Adds a salty, nutty dimension and helps create that irresistible golden crust.
Nutmeg: An optional but traditional addition that magically enhances the flavor of spinach and cream.
Salt and Pepper: Essential seasonings to bring all the flavors into perfect harmony.

Note: You’ll find the complete list of ingredients, along with their exact measurements, in the printable recipe card at the bottom of this post.

Variations

Protein Additions

Transform this side dish into a complete meal by adding protein! Fold in 2 cups of diced cooked chicken, leftover holiday ham, or even jumbo lump crab meat before baking.

Mediterranean Twist

Add ½ cup sun-dried tomatoes and ¼ cup chopped kalamata olives for a Mediterranean flavor profile.

Extra Cheese Options

While gruyere offers wonderful flavor, feel free to substitute or mix with fontina, white cheddar, or gouda.

Veggie Boost

Include other vegetables like sautéed mushrooms, artichoke hearts, or roasted red peppers for additional texture and flavor.

How to Make Spinach Gratin

Step 1: Prepare the Spinach

Preheat your oven to 425°F and coat a 9×11 inch baking dish with non-stick spray. Cook the frozen spinach according to package directions, then thoroughly squeeze out excess moisture. This crucial step prevents a watery gratin!

Step 2: Create the Cream Base

Melt butter in a large skillet over medium-high heat. Add diced onion and sauté until soft and translucent, about 3-4 minutes. Add minced garlic and cook just until fragrant, about 30 seconds—be careful not to burn it!

Step 3: Build the Cheese Sauce

Reduce heat slightly and add cream cheese, stirring constantly until completely melted and smooth. Pour in the heavy cream and cook for 2 minutes to begin thickening. Add 1 cup of the gruyere and all of the parmesan, stirring until melted and velvety.

Step 4: Combine and Season

Fold the drained spinach into the cream sauce, ensuring it’s evenly coated. This is when the magic happens! Season with nutmeg, salt, and pepper to taste. The nutmeg might seem unexpected, but it perfectly complements the creamy spinach.

Step 5: Bake to Perfection

Transfer the spinach mixture to your prepared baking dish and sprinkle the remaining cup of gruyere evenly across the top. Bake for 15-20 minutes until gloriously golden brown with bubbling edges. Let rest for 5 minutes before serving to allow the flavors to settle.

Pro Tips for Making the Recipe

Squeeze That Spinach: Don’t skip thoroughly draining the spinach—this prevents a watery gratin and concentrates the flavor.
Room Temperature Cream Cheese: Take your cream cheese out of the refrigerator 30 minutes before cooking for smoother incorporation.
Freshly Grate Your Cheese: Pre-shredded cheese contains anti-caking agents that can prevent proper melting. Grating your own results in a silkier sauce.
Watch Your Baking Time: Every oven is different, so start checking at the 15-minute mark. You want golden brown cheese, not burnt!
Let It Rest: Those 5 minutes of resting time after baking aren’t just for cooling they allow the sauce to thicken to the perfect consistency.

How to Serve

Perfect Pairings

This rich spinach gratin pairs beautifully with roasted meats like prime rib, grilled steak, or roast chicken. The creamy spinach complements the proteins without overwhelming them.

Holiday Menus

Include this gratin in your Thanksgiving or Christmas spread for a sophisticated upgrade from standard vegetable sides. It holds its own alongside turkey, ham, or beef tenderloin.

Vegetarian Meal

Serve larger portions as a main course alongside a crisp green salad and crusty bread for a satisfying vegetarian dinner.

Wine Pairing

The creamy, cheesy nature of this dish calls for a crisp white wine with good acidity. Try a Sauvignon Blanc or unoaked Chardonnay to cut through the richness.

Make Ahead and Storage

Storing Leftovers

Transfer cooled leftovers to an airtight container and refrigerate for up to 5 days. The flavors actually develop nicely after a day or two!

Freezing

This gratin freezes surprisingly well for up to 6 months in an airtight container. For best results, thaw overnight in the refrigerator before reheating.

Reheating

Warm refrigerated leftovers in a 350°F oven for 15-20 minutes until heated through. You can also microwave individual portions, though the oven method better preserves the texture.

Make Ahead

Prepare the entire recipe up to the baking step, then cover tightly and refrigerate for up to 48 hours. Let it stand at room temperature for an hour before baking as directed, adding a few extra minutes if needed.

FAQs

Can I use fresh spinach instead of frozen?

Yes! You’ll need about 3 pounds of fresh spinach to equal the amount in this recipe. Blanch it briefly in boiling water, then shock in ice water, drain thoroughly, and chop before proceeding with the recipe. Fresh spinach requires more prep work but offers a slightly brighter flavor.
My gratin turned out watery. What went wrong?

The most common culprit is inadequately drained spinach. Frozen spinach contains a surprising amount of water that must be thoroughly pressed out. Use cheesecloth or a clean kitchen towel to squeeze out every drop, or press repeatedly in a fine-mesh sieve.
Can I make this recipe lighter?

While the full-fat dairy creates the luxurious texture that makes this dish special, you can substitute light cream cheese and half-and-half for the heavy cream. The result won’t be quite as rich but will still be delicious. I don’t recommend using fat-free products as they won’t melt properly.
Is this spinach gratin gluten-free?

Yes! Unlike many gratins that use flour to thicken the sauce, this recipe relies on cream cheese and reduction to create the perfect consistency, making it naturally gluten-free.

Final Thoughts

This Spinach Gratin is comfort food at its finest—sophisticated enough for special occasions yet simple enough for weeknight indulgence. The combination of creamy cheese sauce and nutritious spinach creates the perfect balance of decadence and virtue. Whether served alongside your holiday roast or as a satisfying vegetarian main, this versatile dish is bound to become a staple in your recipe collection. Give it a try tonight and watch it disappear!