Set a steamer basket inside a stock pot and add water to fill just up to the basket. Place cauliflower florets in the basket and steam 20 minutes or until very tender.

Meanwhile, preheat broiler to high heat and set rack 6 inches below the element. Lay salmon on an oiled baking sheet. Brush salmon with the avocado oil and season with half of the salt and the pepper. Transfer to oven and broil 7-10 minutes, to desired doneness. 

While salmon and cauliflower cook, make the spinach. Add half of the butter to a saute pan over medium heat. When bubbling, add the garlic and cook 1 minute. Add the spinach and cook 2-3 minutes, stirring. Season with remaining salt. Cover to keep warm. 

Remove the cooked cauliflower and transfer to a deep bowl. Mash well with a potato masher. Add the remaining butter and the coconut milk and mash until smooth and creamy.

Serve broiled salmon over mashed cauliflower with spinach.