Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Trim the woody ends off the asparagus and place the spears on the baking sheet along with the cherry tomatoes.
Mince the garlic and toss the vegetables with 0.5 tablespoon of olive oil, the garlic, and a small pinch of the salt and pepper.
Roast the vegetables for 12 to 15 minutes until the asparagus is tender and the tomatoes have just begun to burst.
While vegetables roast, pat the cod fillet completely dry with paper towels and season both sides with the remaining salt, pepper, and lemon zest.
Heat the remaining 1 tablespoon of olive oil in a stainless steel or cast-iron skillet over medium-high heat until shimmering.
Carefully place the cod in the pan and sear for 3 to 4 minutes without moving it to develop a deep golden crust.
Flip the fillet gently and cook for another 2 to 3 minutes until the fish is opaque throughout and flakes easily with a fork.
Remove from heat, drizzle with fresh lemon juice, and garnish with chopped parsley before serving immediately alongside the roasted vegetables.