1 1/2 pounds frozen spinach, defrosted and drained or I use fresh and just cook for a few minutes in boiling water and shock in cold water
1 large yellow onion, finely chopped
2 cloves garlic, minced
1 cup milk
3/4 cup parmesan cheese, grated, divided
1/2 cup heavy cream
1/2 cup gruyere or swiss cheese, grated
1/4 cup crispy bacon, crumbled
2 tablespoons all-purpose flour
3/4 teaspoon salt, or to taste
1/4 teaspoon freshly ground black pepper, or to taste
1/8 teaspoon nutmeg
Step 1: Preheat oven to 425º F and lightly grease a 9x13-inch baking dish with butter or non-stick spray.
Step 2: Melt butter in a large pan or skillet over medium-high heat and sauté onions until softened and translucent. 6-8 minutes.
Step 3: Add garlic and cook for another 1 minute, or until fragrant, then whisk in flour.
Step 4: Stirring frequently, cook for 2-3 minutes, or until mixture is thickened and smooth.
Step 5: Pour in heavy cream and milk and cook for 5-7 minutes, stirring often, until thick. Add nutmeg.
Step 6: Take drained spinach and add it to cream sauce, along with 1/2 cup parmesan cheese. Season with salt and pepper.
Step 7: Pour creamy spinach mixture into greased baking dish and top with remaining parmesan and gruyere (or swiss). If using, add bacon crumbles on top.
Step 8: Place in oven and bake for 20-22 minutes, or until cheese is hot and bubbly.
Step 9: Remove from oven and let cool 5 minutes before serving.