1. Blanch Spinach: Bring a large pot of salted water to a boil. Prepare a large bowl with ice water. Add the fresh spinach to the boiling water and blanch for about 1-2 minutes, or until wilted. Immediately transfer the spinach to the ice water to stop the cooking process. Drain the spinach and squeeze out as much water as possible. Chop the spinach finely and set aside.
2. Sauté Onion and Garlic: Melt the butter over medium heat in a large skillet. Add the diced onion, and minced garlic, and sauté until the onion becomes translucent, about 4-5 minutes.
3. Add Cream Cheese and Cream: Stir in the softened cream cheese and heavy cream. Cook, stirring constantly, until the cream cheese is fully incorporated and the mixture becomes creamy. Bring to a soft boil on low heat and let thicken for about 8-10 minutes. 
4. Season and Add Spinach: Season the mixture with grated Parmigiano cheese, ground nutmeg, Italian seasoning, salt, and black pepper to taste. Add the chopped spinach to the creamy mixture and stir well to combine.
5. Heat: Cook for an additional 5 minutes, allowing the spinach to heat through and absorb the flavors of the sauce.
6. Serve: Transfer the creamy spinach to a serving dish and serve hot. 

This creamy spinach is a delightful accompaniment to your steak or any other main course. Enjoy!