Pat salmon fillets dry with a paper towel and season with salt and black pepper.
Add oil to a cast iron skillet over medium heat. When a drop of water sizzle, oil is ready. Add the salmon fillets skin side down.
Sear salmon for 3-4 minutes or until skin releases from the pan. Filet will release easily when ready to flip.
Flip salmon then add butter, thyme, garlic, capers and lemon juice.
Cook salmon for an additional 3-4 minutes, or until temperature reaches 125-145° in the thickest part.* While salmon sears on the second side, baste the skin side with butter from the pan.
Using a spoon, scoop capers and butter sauce from pan and add to the top of the salmon before serving.
Notes
*The FDA recommends cooking salmon to a temperature of 145˚ however many chefs pref to cook to a temperature of 125˚ for a flakier and more moist texture.
Wild caught salmon, however, is typically cooked to a slightly lower temperature of 120˚ vs. farm-raised salmon. For more details, see above.
Dill, parsley, chives, basil, tarragon, oregano, or rosemary are all great herb choices if you don't want to use thyme.