Pat the ribeye steaks dry with paper towels to remove excess moisture.
Season both sides of each steak evenly with kosher salt and freshly ground black pepper.
Heat a large cast-iron skillet over medium-high heat until very hot, about 3-4 minutes.
Add the vegetable oil to the skillet and swirl to coat the bottom.
Place the steaks in the skillet and sear without moving for 4 minutes.
Flip the steaks and add the unsalted butter, smashed garlic cloves, and fresh thyme to the skillet.
Tilt the skillet slightly and use a spoon to baste the steaks with the melted butter and aromatics for an additional 4-5 minutes for medium-rare doneness.
Remove the steaks from the skillet and transfer to a plate.
Cover loosely with aluminum foil and let rest for 5 minutes before serving.