Begin by heating a large skillet over medium heat. Melt butter and add diced onion. Saute for 2-3 minutes to soften onion.
Reduce heat to low and add minced garlic and ground nutmeg. Cook for 1 minute until fragrant.
Add cream cheese and stir to combine with onions and garlic. Carefully pour in cream, stirring as you go. Allow to thicken and reduce slightly for 1-2 minutes.
Add chopped fresh spinach and gently stir to wilt. Once wilted, sprinkle in freshly grated parmesan cheese and stir.
Season with salt, black pepper, and fresh lemon juice. Immediately remove from heat.
Serve warm.
Notes
This is a quick and delicate dish. Cook everything over medium to low heat to avoid burning and stay close to the stove during the fast cook time.