Remove steaks from refrigerator 30 minutes before cooking to bring to room temperature.
Pat steaks completely dry with paper towels, then brush both sides lightly with vegetable oil.
In a small bowl, combine salt, black pepper, garlic powder, and onion powder, then generously season both sides of each steak.
Heat a cast-iron skillet over high heat until smoking hot, about 5 minutes.
Place steaks in the skillet and cook without moving for 4-5 minutes until a deep brown crust forms.
Flip steaks and cook for another 4-5 minutes for medium-rare, or until desired doneness is reached.
Add butter and thyme sprigs to the pan, tilting the skillet and spooning the melted butter over the steaks for 1 minute.
Remove steaks from skillet and let rest on a cutting board for 5-10 minutes before serving.
Serve with the pan butter drizzled over the top.