Peel and chop the yellow potato into 1-inch cubes.
Place potato cubes in a small pot of salted water, bring to a boil, and cook for 10-12 minutes until fork-tender.
While potatoes cook, combine smoked paprika, garlic powder, onion powder, dried thyme, cayenne pepper, 0.125 tsp sea salt, and 0.125 tsp black pepper in a small bowl.
Pat the salmon fillet dry with a paper towel and coat the flesh side evenly with the spice rub.
Heat olive oil in a non-stick skillet over medium-high heat.
Place salmon in the skillet, spice-side down, and sear for 3-4 minutes until a dark, crispy crust forms.
Flip the salmon and cook for another 2-3 minutes until the internal temperature reaches 145°F.
Drain the cooked potatoes and return them to the pot with the minced garlic clove and ghee.
Mash the potatoes until smooth, seasoning with the remaining sea salt and black pepper.
Plate the garlic mashed potatoes and top with the blackened salmon fillet.