Spinach Gratin

Adapted from a recipe in “Barefoot Contessa Parties”

Serves 8-10

Ingredients:
4 tablespoons (1/2 stick) butter
1 large sweet onion, chopped

2 cloves garlic, minced
1/4 cup flour
1/4 teaspoon grated nutmeg
1 cup heavy cream
2 cups milk
3 pounds frozen chopped spinach, defrosted (5 (10-ounce) packages)
1 cup freshly grated Parmesan cheese
1 tablespoon kosher salt
1/2 teaspoon freshly ground black pepper
1/2 cup grated Gruyere cheese (or your favorite blend)

¾ cup French Fried onions

Directions :
Preheat the oven to 425 degrees F.

Melt the butter in a large skillet over medium heat. Add the onions and saute until translucent, about 10 minutes. Add the flour and nutmeg and cook, stirring, for 2 more minutes. Add the cream and milk and cook until thickened, stirring often. Squeeze as much liquid as possible from the spinach and add the spinach to the sauce. Add 1/2 cup of the Parmesan cheese and mix well. Season, to taste, with salt and pepper.

Transfer the spinach to a 9x13 baking dish or gratin dish and sprinkle the remaining 1/2 cup Parmesan and the Gruyere on top. Bake for 20 minutes until hot and bubbly. Serve hot.

Note: You can make this ahead and put the spinach mixture in a covered bowl in the refrigerator.  Before baking, bring it to room temperature and then bake as directed above.