Peel and cube the sweet potato, then boil in water until tender, approximately 15 minutes.
Drain the potatoes and mash thoroughly with the ghee and a pinch of sea salt until smooth.
Pat the salmon fillet dry with paper towels and season both sides with salt and black pepper.
Heat avocado oil in a non-stick skillet over medium-high heat.
Place salmon in the pan skin-side down and sear for 4-5 minutes until the skin is crisp.
Flip the salmon and cook for another 2-3 minutes until cooked through to your preference, then remove from the pan.
In the same pan, add the minced garlic and sauté for 30 seconds until fragrant.
Add the fresh spinach to the pan and toss until just wilted, about 1-2 minutes.
Plate the sweet potato mash, top with the garlicky spinach, and place the salmon on top.
Finish with a fresh squeeze of lemon juice over the fish and serve immediately.