Drizzle the olive oil over the salmon fillets and season the top side up with salt and pepper.
Add butter to a non-stick iron skillet. Place the cast iron skillet over high heat and, once hot, add the salmon fillets into it, skin side down.
Cook the salmon for three minutes, before reducing the heat to medium and flipping the fish. Cook for a further two minutes.
Transfer the salmon to a plate and drizzle with the buttery pan juices. Serve with sliced lemons.
