Start with the herb butter 2 hours ahead. In a small bowl, combine butter, garlic, herbs and black pepper with a fork. Transfer the herb butter to a plastic wrap. Press the butter into 1½-inch diameter roll. Wrap in plastic wrap and chill in the fridge. If you want to make the roll perfectly round, you can reshape it once it is slightly hardened, about 20 minutes or so.
For the steak, pat dry with paper towels. Season with salt and pepper. Place the steak with 2 sprigs thyme in a sous vide bag or a large freezer Ziploc bag. Seal and set aside.
Preheat the sous vide cooker in a large pot of water to the desired final temperature, 125˚F for rare, 130˚F for medium-rare, 140˚F for medium, 150˚F for medium-well & 156˚F for well done (I did 130˚F). Place the sous vide bag inside the water bath. Make sure the meat is submerged under water. Cook for 1 – 2½ hours (I cooked mine for 1 hour 15 minutes.).
Once cooked, remove steak from bag and pat dry with paper towels.
Meanwhile, in a medium cast iron or heavy skillet over high heat, heat until very hot. Add 1 tablespoon vegetable oil. Place the steak into the skillet, press down for a better seared. Cook until nicely brown, about 30 – 40 seconds. Flip and cook the other side, 30 – 40 more seconds. Turn the steak on the side and get a quick sear. Transfer the steak to a serving plate. Top with ½-inch thick herb butter. Serve.