- Cook spinach in microwave according to package directions. Remove excess water (squeeze carefully using cheese cloth, a tea towel, or a colander) and set aside.
- In a large skillet over medium high heat, melt butter. Add onion and sauté until translucent.
- Add garlic and cook for 30 seconds. Add cream cheese and cook, stirring, until melted.
- Add heavy cream and cook for 2 minutes. Add mozzarella cheese, parmesan cheese, salt, pepper, and nutmeg. Stir till combined.
- Fold in spinach into cream sauce and cook for an additional minute to reheat spinach.
- Serve immediately or store in an airtight container in the fridge for up to a week. The leftovers reheat great and you can also freeze it!