•3 tbsp light butter (I used Land O Lakes)
•1 cup finely chopped onion
•1/4 cup flour
•1/4 tsp fresh grated nutmeg
•3 cups 2% milk
•3 lbs (3 16-oz packages) frozen chopped spinach, defrosted
•3/4 cup freshly grated Parmesan cheese
•1 tbsp kosher salt
•1/2 tsp freshly ground black pepper
•1/2 cup shredded Swiss Gruyere cheese (I used Sargento)

Preheat the oven to 425°.

In a heavy-bottomed saute pan melt the butter over medium heat. Add the onions and sauté until translucent, about 10 - 12 minutes.

Add the flour and nutmeg; cook 2 more minutes, stirring occasionally.

Add the milk and cook until thickened, about 5 - 7 minutes.

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 large baking dish and sprinkle the remaining 1/4 cup Parmesan and the Swiss cheese on top.

Bake for 20 minutes until hot and bubbly. Serve hot. Makes a little over 6 1/2 cups.