Combine all marinade ingredients (not butter and oil) in a large dish and whisk. Place filets in the marinade, coating well and cover with plastic wrap. Marinate in the refrigerator overnight or for several hours.
Heat up a large skillet over medium with the butter and oil. Once melted remove salmon filets form the marinade and place in the skillet, cut side down. Let cook for about 7 minutes. Flip the filets onto the skin side and cook another 5 minutes. Transfer the filets to a plate and with the heat still on, add the leftover marinade to the skillet. Turn the heat to high and let the sauce bubble and reduce, swishing it around occasionally in the pan. When it has thickened to your liking pour over the fish. Serve and enjoy.