01 - Remove leaves and core from cauliflower, cut into florets, and pulse in a food processor until grains resemble rice.
02 - Melt half the butter in a large skillet over medium heat. Add chopped onions and cook 2-3 minutes until translucent.
03 - Add minced garlic and sliced mushrooms to the skillet; sauté for 4-5 minutes until softened.
04 - Stir in riced cauliflower, cooking for 3-4 minutes while stirring frequently.
05 - Pour in vegetable broth and heavy cream. Stir well, reduce heat to medium-low, and simmer 8-10 minutes until cauliflower is tender and most liquid absorbed.
06 - Add baby spinach, remaining butter, and Parmesan cheese. Stir until spinach wilts and mixture becomes creamy, about 2 minutes.
07 - Season with sea salt, black pepper, and nutmeg. Stir in chopped parsley.
08 - Serve warm, garnished with extra Parmesan cheese and parsley if desired.