Allow the salmon to come to room temperature while preheating your oven to 190°C (380°F). Prepare a large baking tray by lining it with aluminum foil and lightly spraying it with cooking spray. Arrange half the lemon slices on the tray as a base.
Combine the melted butter, olive oil, and minced garlic in a bowl, whisking until evenly blended.
Place the sockeye salmon onto the prepared baking tray. Drizzle the garlic butter mixture over the fish, ensuring it is coated well. Season generously with salt and pepper.
Fold the edges of the foil upward slightly to create a barrier. Bake the salmon for approximately 17 minutes, or until it is tender on top. Alternatively, check for an internal temperature of 145°F (63°C).
Remove the salmon from the oven, garnish with the remaining lemon slices and fresh dill. Cover with foil and allow the fish to rest for 5 minutes before serving.