Bring steak to room temperature. Avoid cooking steak cold.
Preapre other ingredients - cut butter into smaller pieces, and crush garlic cloves.
Pat dry steak and sprinkle salt and pepper on both sides (only add salt and pepper to steak when ready to cook).
Add vegetable oil to cast iron. Heat on medium to medium high heat. Once cast iron is hot, sear steak on one side for a few minutes until it is slightly golden brown. Do not move the steak until it is ready to flip. Flip, then sear on the other side.
Add 2 tbsp of butter to cast iron (spread them out around the steak), then add crushed garlic and fresh thyme.
Lower to medium/medium low heat after flipping the steaks. This will ensure the inside of the steak gets cook before the outside burns and becomes too crusty/hard. Adjust the heat as you see fit. The thicker the steak, the lower the heat you will need because thicker steaks will take longer cook.
Use a spoon and scoop melted butter and drizzle onto the top of the steak a few times. Add more butter if the bottom of the cast iron has dried out.
Use a meat termometer to check the temperature of the thickest part of the steak and other random spots on the steak. Once it is ready, remove from heat.
Place steak on a plate and wrap with aluminium foil. Let it sit for 3-5 minutes.
Optional: Add more butter to steak if desire! :)
Serve and enjoy!