Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Scrub the russet potato clean and slice it into even 1/2-inch thick wedges.
In a medium bowl, toss the potato wedges with 0.5 tbsp of olive oil, garlic powder, dried oregano, and a pinch of sea salt and pepper.
Spread the potatoes in a single layer on the baking sheet and roast for 20 minutes.
Trim the woody ends off the asparagus and toss the spears with the remaining 0.5 tbsp of olive oil and a pinch of salt.
After 20 minutes, flip the potato wedges and add the asparagus to the same baking sheet; roast for another 10-12 minutes until the potatoes are golden and the asparagus is tender.
Pat the cod fillets completely dry with a paper towel to ensure a perfect sear, then season both sides with the remaining salt and pepper.
Heat a high-quality non-stick skillet over medium-high heat.
Place the cod in the hot pan and sear for 3-4 minutes per side until the fish is opaque and flakes easily with a fork.
Plate the seared cod alongside the roasted vegetables and finish with a bright squeeze of fresh lemon juice.