Cut the steak into 4-5 strips along the grain, each strip about 5 inches long. Season each piece with salt and pepper on both sides.
Heat oil in a large cast iron pan over medium-high heat. Once the oil starts to smoke, add the meat and cook for 2-3 minutes until you see some nice browning. Flip and cook for another 2-3 minutes or a bit longer, until desired doneness is achieved. 2-3 minutes per side will produce medium-rare doneness. I like using an instant read thermometer to eliminate guessing and cook to 125F - 130F. Transfer the meat to a cutting board and let it rest for 5 minutes.
While the meat is resting, microwave the butter in a wooden or plastic bowl/container for about 7-10 seconds, until very soft but not fully melted. Add the rest of the ingredients and mix well with a spoon. Taste for salt and adjust as needed; set aside.
Slice the meat across the grain and transfer to a serving platter. Spoon the chili butter over the steak slices. Sprinkle chopped cilantro on top and serve with your favorite side dish.