Spinach Gratin
A blend of spinach, white sauce, and cheese baked together into a hearty, comforting casserole.
Serves8 to 10
Prep15 minutes
Cook50 minutes to 55 minutes
Spinach gratin is a decadent, cheesy side dish that makes eating your greens really easy and tasty. It’s a bubbling combination of a few pounds of spinach baked with a white sauce loaded with nutty Gruyère cheese, all topped with a sprinkling of buttery, crunchy breadcrumbs. While gratin is a French word for this type of dish, it really is just a vegetable casserole. Add this to your next dinner party or holiday menu, as it’s right at home next to a big roast or glazed ham.
How Do I Make Spinach Gratin from Scratch?
Here’s how to make spinach gratin.
- Prep the spinach. If you’re using frozen spinach, thaw and squeeze out the excess liquid. For fresh spinach, blanch baby spinach until wilted, then squeeze dry and chop.
- Make the sauce. Sauté onion in butter until softened, then add flour and then milk to make a white sauce similar to a béchamel. Stir in lots of shredded Gruyère cheese to make a cheese sauce.
- Assemble the gratin. Add the spinach to the sauce and make sure to break up any large clumps of spinach. Transfer to the baking dish.
- Top and bake. Sprinkle a mixture of melted butter, panko breadcrumbs, and grated Parmesan cheese on top. Bake until bubbling and the breadcrumbs on top are browned and crunchy.
What Should I Serve with Spinach Gratin?
Spinach gratin is similar to creamed spinach, so it pairs well with things like roast beef or prime rib or roasted lamb. A meaty white fish like halibut also goes nicely with spinach gratin, but honestly it’s so delicious you can even just scoop it up with crackers or crudités like a dip!
Can I Make Spinach Gratin in Advance?
There are two ways you can make spinach gratin ahead of time. You can just bake the whole thing and then reheat in a 350ºF oven until warmed through, but because it’s quite a dense mixture, reheating will take 30 to 40 minutes. Another way is to make the sauce and prep the spinach ahead of time and refrigerate them separately. When you’re ready to bake, rewarm the sauce and then stir in the spinach. Transfer into the baking dish and bake as directed.
Spinach Gratin Recipe
A blend of spinach, white sauce, and cheese baked together into a hearty, comforting casserole.
Prep time 15 minutes
Cook time 50 minutes to 55 minutes
Serves 8 to 10
Nutritional Info
Ingredients
Cooking spray or butter, for coating the baking dish
- 3 pounds
or 5 (10-ounce) packages frozen chopped spinach (see Recipe Notes if using fresh spinach)
- 6 ounces
Gruyère cheese
- 1/2
medium yellow onion
- 5 tablespoons
unsalted butter
- 1 1/4 teaspoons
kosher salt, divided, plus more as needed
- 1/4 cup
all-purpose flour
- 3 cups
whole or 2% milk
- 1/4 teaspoon
freshly grated nutmeg
- 1/3 cup
panko breadcrumbs
- 2 tablespoons
grated Parmesan cheese
Instructions
Arrange a rack in the middle of the oven and heat the oven to 425ºF. Coat an 8- or 9-inch square or other 2-quart baking dish with cooking spray or butter.
Place 3 pounds frozen chopped spinach in a large microwave-safe bowl. Microwave in 1-minute bursts, breaking up any large blocks of spinach with your hands as they start to thaw, until completely thawed, 7 to 8 minutes total. Meanwhile, grate 6 ounces Gruyère cheese on the large holes of a box grater (about 1 1/2 cups). Dice 1/2 medium yellow onion (about 1 cup).
Transfer the thawed spinach into a colander set in the sink. Squeeze the spinach a handful at a time to remove as much moisture as possible and return to the bowl.
Melt 5 tablespoons unsalted butter in a Dutch oven or large pot over medium heat. Transfer 1 tablespoon into a small, heatproof bowl.
Add the onion and 1/4 teaspoon of the kosher salt to the remaining butter in the pot and cook over medium heat, stirring occasionally, until softened, about 5 minutes. Sprinkle with 1/4 cup all-purpose flour and stir constantly for 1 minute to cook out the floury taste. While stirring constantly, slowly pour in 3 cups whole or 2% milk and stir until the flour is completely dissolved. Bring just to a full simmer over medium-high heat, stirring frequently. Add the Gruyère, remaining 1 teaspoon kosher salt, and 1/4 teaspoon freshly grated nutmeg, and stir until the cheese is melted and the sauce is bubbling. Remove the pot from the heat.
Add the spinach and stir until well-coated in the sauce, smashing any clumps into the bottom of the pot or the sides to break them up. Taste and season with more kosher salt as needed. Transfer to the baking dish and spread into an even layer.
Add 1/3 cup panko breadcrumbs and 2 tablespoons grated Parmesan cheese to the reserved bowl of melted butter and stir to combine. Sprinkle the gratin with the breadcrumb mixture.
Bake until the gratin is golden-brown on top and bubbling around the edges, about 30 minutes. Let cool for 5 minutes before serving.
Recipe Notes
Fresh spinach: If using fresh spinach, blanch 4 pounds baby spinach in a large pot of boiling water just until wilted, then drain and rinse under cold water. Squeeze handfuls of the spinach to remove as much water as possible, then coarsely chop before proceeding with the recipe.
Make ahead: The sauce can be made up until the cheese is added but not the spinach up to 2 days ahead. Let cool and refrigerate in an airtight container. Bring the sauce back to a simmer over medium heat before proceeding with the recipe.
The gratin can also be baked, cooled, and refrigerated up to 1 day ahead. Reheat uncovered in a 350ºF oven until warmed through, 30 to 40 minutes.
Storage: Leftovers can be refrigerated in an airtight container for up to 4 days.