Step 1

Preheat oven to 425 degrees F.

Step 2

Melt 4 tablespoons of butter in a large skillet over medium heat. Add the garlic and cook for 1 minute.  Add the mushrooms and sprinkle with salt and pepper. Saute' until the mushrooms are golden brown, about 5 to 7 minutes.

Step 3

Add the spinach ad continue to cook until the spinach has wilted.  Transfer the mixture a 1 1/2 quart oval baking dish.

Step 4

In the same skillet, melt the remaining 2 tablespoons of butter over medium heat. Add the cream and nutmeg and cook until bubbles appear around the edges. Stir in the Parmesan and continue to cook until the mixture has thickened, 3 to 4 minutes.

Step 5

Pour the cream mixture over the spinach and mushrooms. Sprinkle with Gruyere cheese. Bake for 18-22 minutes until the cheese is bubbly and lightly browned.