Preheat your oven to 400°F (200°C) and line a small baking sheet with parchment paper.
Cut the Yukon Gold potato into small 1/2-inch cubes and toss them in a bowl with half of the olive oil, garlic powder, and a pinch of salt and pepper.
Spread the potatoes on the baking sheet and roast for 15 minutes.
Trim the woody ends off the asparagus and add them to the baking sheet with the potatoes, drizzling with the remaining olive oil and another pinch of salt.
Return the vegetables to the oven for 10-12 minutes until the potatoes are golden and the asparagus is tender.
While vegetables roast, pat the sea bass fillet completely dry with a paper towel and season both sides with the remaining salt and pepper.
Heat a high-quality non-stick skillet over medium-high heat. Once hot, place the fish in the pan skin-side down and press gently with a spatula for 30 seconds to ensure even contact.
Sear for 4-5 minutes until the skin is very crispy, then carefully flip and cook for another 2-3 minutes until the flesh is opaque and flakes easily.
Plate the sea bass alongside the roasted potatoes and asparagus. Squeeze the fresh lemon juice over the fish and garnish with chopped parsley.