Steam the bag of frozen cauliflower for 10 minutes.
Heat a non-stick skillet over medium heat. Add a piece of garlic puck , brussel sprouts and thyme. Cook for 2 minutes, then add 1 tbsp of water and cover with a lid and cook for 2-3 minutes, or until desired tenderness, adding a bit more water if necessary. Meanwhile, pat-dry your fillet of fish with paper-towel and set aside.
Transfer the cooked brussel sprouts onto a plate, and return the pan back to the stove-top. Add 1 tbsp of avocado oil, and place your fish fillet, skin-side down on the pan. Season with salt and pepper. Cook for 2 minutes, then flip it over and continue to cook for a minute. Cover with the lid, and continue cooking the fish for 2 minutes. Remove the lid and flip the fish fillet once more to crisp up the skin, about 1 minute.
Meanwhile, using a slotted spoon, transfer the cooked cauliflower into a blender. Puree until smooth and adjust seasoning with salt and pepper. Grab a plate and serve your brussel sprouts, whipped cauliflower and pan-seared arctic char.