01 - Wash and trim the spinach. If using fresh, roughly chop.
02 - In a large skillet over medium heat, melt the butter. Add the onion and sauté for 2 to 3 minutes until translucent.
03 - Add the garlic to the skillet and cook for 1 minute until fragrant.
04 - Add the spinach and cook, stirring, until wilted—about 3 to 4 minutes for fresh spinach or 2 minutes for thawed frozen spinach.
05 - Pour in the heavy cream and stir well. Let the mixture simmer gently for 5 minutes until slightly thickened.
06 - Stir in the grated Parmesan cheese and ground nutmeg. Season with salt and black pepper. Simmer for 1 to 2 minutes more until creamy.
07 - Serve hot as a side dish or over rice, pasta, or toast.