"SPINACH GRATIN"

From Ina Garten's Barefoot Contessa Parties

4 tablespoons unsalted butter (1/2 stick)
4 cups chopped yellow onions (2 large)
1/4 cup all-purpose flour
1/4 teaspoon nutmeg
1 cup heavy cream
2 cups milk
3 pounds frozen chopped spinach, defrosted (5 10-oz. packages)
1 cup freshly grated Parmesan cheese
1 tablespoon kosher salt
1/2 teaspoon freshly ground pepper
1/2 cup grated Gruyere cheese (or you could use Swiss)

Preheat oven to 425 degrees.

Melt the butter in a heavy-bottomed saute pan on medium heat.  Add the onions and saute until translucent, about 15 minutes.  Add the flour and nutmeg and cook, stirring, for 2 minutes.  Add the cream and milk and cook until thickened.

Squeeze as much liquid as possible from the spinach and add the spinach to the sauce.  Add 1/2 cup Parmesan cheese and mix well.  Season to taste with the salt and pepper.

Transfer the spinach to a baking dish and sprinkle the remaining 1/2 cup Parmesan and the Gruyere on top.  Bake for 20 minutes, or until hot and bubbly.  Serve immediately.  YIELD:  8 servings

**You can assemble this dish with the cheese topping a day or two ahead, then bake it before serving.