4 tablespoons butter
1 small onion, finely chopped
1/2 lb fresh mushrooms, sliced
3 garlic cloves, minced (or to taste)
2 cups light cream
2 (10 ounce) packages frozen spinach, thawed and squeezed dry
1/4 cup grated parmesan cheese (or to taste)
3 tablespoons all-purpose flour
1 teaspoon salt, to taste (I use seasoned salt)
1/4 teaspoon nutmeg
fresh ground black pepper
3/4 cup grated gruyere cheese or 3/4 cup swiss cheese, divided
Pre-heat your oven to 325 degrees F.
Grease a 9×9 oven proof casserole dish, or an oval or round casserole dish of the same proportions
Melt the butter over medium high heat in a skillet. I use a non stick here but any will do.
Do a quick toss of the onions, mushrooms and the garlic in the melted butter, stirring to soften them. About 4 minutes.
Whisk in the flour and spices (salt, pepper and nutmeg), whisk for 2 minutes.
Gradually add in the cream, continue whisking until thick and until the mixture reaches a light boil, remove from heat then mix in 1/4 cup grated Gruyere or Swiss cheese, stir until cheese melts, (taste for extra seasoning).
In the prepared casserole dish spread half of the spinach, then top the spinach with 2 Tbsp grated Parmesan cheese; then cover with half of the mushroom/cream sauce, then repeat.
Top the casserole with 1/2 cup grated Gruyere or Swiss cheese.
Bake for 25-35 minutes, or until hot and bubbly and the cheese is browned to your liking.