Step 1: Preheat oven to 200°C (400°F). Line a baking sheet with parchment paper.
Step 2: Place trimmed asparagus on the baking sheet. Drizzle with olive oil, season with salt and pepper, and toss to coat evenly. Roast in the oven for 10–12 minutes until tender but still crisp.
Step 3: While asparagus is roasting, melt butter in a small saucepan or microwave. Stir in minced garlic, lemon juice, and lemon zest.
Step 4: Pat salmon fillets dry and season with salt and black pepper. Heat a skillet over medium-high heat and sear salmon skin-side down for 2–3 minutes until golden brown. Flip and sear the other side for 1–2 minutes.
Step 5: Brush the garlic-lemon butter over the salmon fillets. Transfer salmon to the oven with the roasted asparagus for an additional 3–5 minutes to finish cooking. Salmon should be opaque and flaky.
Step 6: Remove from oven and garnish with chopped fresh parsley or dill. Serve immediately alongside the roasted asparagus.