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Spinach gratin is a rich and creamy side dish with a layer of crispy melty cheese on top. This fancy side is easy to make ahead and freezer-friendly. |

Spinach Gratin

  • Author: Sam Hu | Ahead of Thyme
  • Total Time: 35 minutes
  • Yield: 6 servings
  • Diet: Vegetarian


Spinach gratin is a rich and creamy side dish with a layer of crispy melty cheese on top. This fancy side is easy to make ahead and freezer-friendly.


  • 1 + 1/2 lb. fresh spinach (3 bunches), stems removed
  • 2 tablespoons butter
  • 1 small onion, diced
  • 1 tablespoon garlicminced
  • 1/2 tablespoon all-purpose flour or cornstarch
  • 1 + 1/2 cups heavy cream
  • 1/2 cup Parmesan cheese, grated, divided
  • 1 teaspoon salt (or to taste)
  • 1/2 teaspoon ground black pepper
  • 1 cup mozzarella cheeseshredded


  1. Preheat oven to 350F.
  2. Cut fresh spinach in half and cook in a large pot of boiling water for 30 seconds until wilted. Rinse the spinach under running cold water until cool to handle. Drain it in a colander and squeeze out excess water. Set aside.
  3. In a large skillet, melt butter over medium-high heat until melted butter turns bubbly, about 1-2 minutes. Sauté onion and garlic until fragrant, about 2 minutes.
  4. Add flour and stir well to combine. Stir in heavy cream and 1/4 cup of Parmesan. Stir constantly and turn the heat down to medium. Bring the mixture to a simmer until smooth and thickened, about 4-5 minutes. Season with salt and pepper to taste.
  5. Stir in spinach and toss well to coat. Cook for 1 -2 minutes until heated through. 
  6. Transfer spinach mixture to a 9-inch square baking pan and top with mozzarella and remaining 1/4 cup Parmesan. Bake for 20 minutes until cheese is melted and golden brown. Alternatively, you can place it under the broiler on high for 2-3 minutes until melted and golden. Keep a close eye on the broiler because things can burn quickly. 


What to pair with spinach gratin: Spinach gratin is a versatile dish that tastes good with virtually any protein: chicken, beef, pork, fish, and anything else you can think of! It also tastes amazing with pasta, rice, and potatoes.

Make ahead instructions: Make this recipe and assemble the spinach gratin up until the baking step. Then cover with plastic cling wrap and store in the refrigerator up to a day or 2, until ready to serve. If it has been sitting in the fridge for a while, you will need to add 10 minutes to the bake time.

How to store: You can keep leftover spinach gratin in the fridge for up to 3-4 days. Cover the dish with plastic wrap or tin foil or transfer it to an airtight container before storing. You can also freeze it for up to 3 months.

How to reheat: Reheat spinach gratin in a 350F preheated oven for 10-20 minutes until warmed through. You can also reheat it, covered, in the microwave in a microwave safe bowl on medium heat in 20 second intervals. 

  • Prep Time: 5 minutes
  • Cook Time: 30 minutes
  • Category: Side Dish
  • Method: Baked
  • Cuisine: American

Keywords: spinach gratin, how to make spinach gratin, creamy baked spinach, creamy spinach, cheesy spinach