four10-ounce packages of frozen spinachdefrosted and excess moisture squeezed out
1/4cupcream cheesesoftened and at room temperature
1/4cupfreshly grated Parmesan
1cupgrated Swiss or Gruyere cheese
salt and black pepper to taste
Buttery Panko Topping
1 1/2cupspanko crumbs
1/4cupsalted butter melted
1/2cupfreshly grated Parmesan cheese
Preheat your oven to 375° F. Grease a 9x13 pan with butter and set aside.
Prepare your spinach and set aside on paper towels to help it drain even more while you prepare the cheese sauce. This takes a lot of time, make sure to do this now before you start the sauce!
Melt the butter in a large, heavy bottomed saucepan over medium heat. Add in the onions and sauté until they are soft and translucent, about 15 minutes.
Add the garlic and sauté until browned and fragrant, about 2 more minutes.
Add in the flour and cook, stirring constantly, until browned, around 2-3 minutes. (This adds flavor to the roux.) Add in the nutmeg and mix in.
Pour in one cup of the milk slowly, whisking the mixture to ensure that there are no lumps. Once you have added it and the mixture is smooth and creamy, you can add the remaining milk and the cream, whisking constantly to keep it smooth.
Stir in the cream cheese, Parmesan, and gruyere cheese, and keep stirring until they have melted in.
Stir in the spinach.
Season now with salt and pepper to taste.
Spoon the spinach filling into the prepared 9x13 pan.
In a small bowl, combine the topping ingredients until mixed together completely.
Sprinkle over the casserole in an even layer.
Bake in the preheated oven for 25-30 minutes until hot and bubbly. Cover the top with aluminum foil if the topping starts to brown too quickly.
Remove and let stand for 5 minutes before serving.
You can adjust the topping to your liking, adding some spices if you like!