Trim the asparagus, mince the garlic, and zest and juice the lemon.
Combine melted butter, minced garlic, lemon juice, lemon zest, and oregano in a bowl. Season with salt and pepper.
Place asparagus on a baking sheet and drizzle half of the lemon garlic butter over it. Toss to coat.
Place salmon fillets on the baking sheet and drizzle the remaining lemon garlic butter over them.
Bake in a preheated oven at 400°F for 12-15 minutes until salmon flakes easily and asparagus is tender.
Garnish with lemon slices and chopped parsley before serving.