Easy Make-Ahead Spinach Gratin is a perfect side dish for your holiday meals with its creamy, cheesy goodness. Frozen spinach is mixed with a classic Mornay sauce accented with caramelized onions. It's topped with both Gruyère cheese and freshly grated Parmesan cheese to create an unforgettable dish. As an added bonus, it can be made ahead of time and produces amazing leftovers.
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Health Benefits of Spinach
This is going to highlight my age, but when I was growing up, Popeye proclaimed that he was "strong to the "Finich", 'Cause I eats me spinach, I'm Popeye the Sailor Man." There was a good reason that spinach was the main reason for his beating Brutus.
Spinach, which is a green, leafy vegetable, is rich in vitamins A, C, and K, magnesium, iron, and manganese. It can help strengthen bones, eyesight, and the immune system.
The vitamin A in spinach helps skin and mucous membranes repel various kinds of bacteria and viruses effectively. Vitamin C promotes a healthy heart and taken together, spinach helps keep one energized.
Ingredients: Here's What You'll Need
- The Vegetables: I like to use frozen spinach for this amazing dish as opposed to fresh spinach for several reasons, and added onion for extra flavor.
- Cheeses: I used a combination of Parmesan Cheese and Gruyère cheese in this recipe.
- Mornay Sauce: For the Mornay Sauce, I used unsalted butter, all-purpose flour, Kosher salt, pepper, and freshly grated nutmeg.
Here's How to Make This Delicious Spinach Gratin
- Start by squeezing as much liquid as possible from thawed frozen spinach by hand. Then, place the spinach in a double layer of paper towels and squeeze out the remaining liquid.
- Melt the butter in a large skillet over medium heat for the sauce. Add the onions and sauté until lightly browned. This takes about 15 minutes.
- Once the onions are lightly browned, add the flour, salt, pepper, and nutmeg to the skillet. Stir to combine and let the mixture cook for about 2 minutes to remove the raw flour taste.
- Then, add the milk and cook the sauce until it is bubbly and thickened.
- Once the sauce is thickened and bubbly, add freshly grated Parmesan cheese; stir until the cheese is melted.
- Finally, add the spinach and stir everything together until all of the ingredients are well incorporated.
Here's How to Finish the Spinach Gratin
Transfer the Spinach Gratin mixture to a casserole dish sprayed with nonstick spray.
Then, sprinkle on shredded Gruyère cheese and more freshly grated Parmesan cheese.
One of the nice things about this dish is that it can be made ahead of time up to this point, covered, and refrigerated.
Bake the Spinach Gratin in a preheated 425°F oven for about 20 minutes, adding about 10 minutes if made in advance.
Talk about good! The spinach gratin was perfectly seasoned and full of cheesy goodness. In other words, it was absolutely delicious.
This cheesy spinach gratin is a great recipe to make to grace your holiday table or everyday table for that matter. Yum!
Recipe Frequently Asked Questions
A gratin is a dish that is usually made with a creamy sauce and topped with a layer of cheese or breadcrumbs.
Spinach gratin is a versatile dish that goes well with many main courses, such as roasted chicken, baked fish, grilled pork, or steak. It also makes a great side dish for a vegetarian meal.
Spinach gratin can be made ahead of time, covered, and refrigerated until you are ready to bake it. You'll need to add a few extra minutes to the baking time if the dish is cold when you put it in the oven.
Spinach gratin will keep in the refrigerator for up to 3-4 days. Be sure to store it in an airtight container to keep it fresh.
Spinach gratin can be frozen. Just be sure to wrap it tightly in plastic wrap or foil and then place it in an airtight container or freezer bag. It will keep in the freezer for up to 2-3 months. To reheat, thaw it in the refrigerator overnight and then bake it in the oven until heated through.
Recipe Tips and Tricks
- The nutmeg added to the Mornay sauce provides a subtle enhancement to the sauce. I like to use fresh nutmeg. However, you can also use ground nutmeg in this dish.
- Either whole milk to 2% milk will work fine in this recipe for the Mornay sauce.
- One of the beauties of this dish is that you can prepare it in advance for up to a day. Cover the casserole dish with aluminum foil and refrigerate it. Add 5 minutes or so to the cooking time to compensate for the fact that the Spinach Gratin is cold from the refrigerator.
- The leftovers are as good, if not better. I generally heat the leftovers for several minutes in the microwave.
Other Delicious Spinach Dishes
If you like spinach, you should definitely try these other amazing dishes with spinach as the star:
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Recipe
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Easy Make-Ahead Spinach Gratin
Ingredients
- 24 ounce package frozen chopped spinach, thawed
- 2 Tablespoons unsalted butter
- 2 cups finely chopped onion (1 large onion)
- 2 Tablespoons all-purpose flour
- 1 teaspoon Kosher salt
- ¼ teaspoon freshly ground black pepper
- ⅛ teaspoon freshly grated nutmeg (See Tip 1)
- 1 ½ cups milk (See Tip 2)
- ½ cup (2 ounces) freshly grated Parmesan cheese, divided
- ½ cup shredded Gruyère cheese
Instructions
- Preheat oven to 425°F. Spray a 2-quart casserole dish with non-stick spray. Set aside.
- By the handful, squeeze as much water as possible from the spinach. Repeat with paper towels. Set aside.
- Melt the butter in a large skillet over medium heat. Add the onions and sauté until lightly browned about 15 minutes. Add the flour, salt, pepper, and nutmeg. Cook, stirring, for 2 more minutes. Add the milk and cook until thickened. Add ¼ cup of grated Parmesan cheese. Stir until melted. Add the spinach; mix well.
- Transfer to the prepared casserole dish. Top with Gruyère cheese and remaining Parmesan cheese. May be prepared in advance up to this point. (See Tip 3)
- Bake in preheated 425°F oven for 20 minutes or until hot and bubbly.
- Yield: 6 servings. (See Tip 4)
Video
Tips/Notes
- I like to use fresh nutmeg. However, you can also use ground nutmeg in this dish.
- I used whole milk, but feel free to use 2% milk.
- You can prepare this in advance for up to a day. Cover the casserole dish with aluminum foil and refrigerate. Add 5 minutes or so cooking time to compensate for the fact that the Spinach Gratin is cold from the refrigerator.
- The leftovers are as good, if not better. I generally just heat the leftovers for several minutes in the microwave.
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