Cook pasta until al dente, following package directions omitting salt. Before draining, reserve at least ½ cup of pasta cooking water and set aside.
Meanwhile, heat the olive oil in a large skillet over medium heat.
Add garlic and cook for about 1 to 2 minutes until fragrant.
Add part of the spinach and season with salt. Stir until wilted adding handfuls of spinach at a time.
When the spinach is wilted, but still bright green, stir in cream cheese and 1/3 cup pasta water. Save remaining pasta water to loosen the sauce, if needed.
Add grated parmesan cheese and nutmeg to the sauce and stir well.
Drain pasta and add to the skillet. Serve immediately with a drizzle of olive oil and black pepper.