Pan-sear in a hot cast iron with butter over high heatm, about 2–3 minutes per side for medium-rare. It's thinner and uneven in shape, so it cooks fast. Watch it.
Or slice it thin and use it anywhere you'd want tender, quick-cooking beef: stir fry, beef tips over noodles, a fast weeknight sauté.
Don't overthink it. High heat, short cook time, rest a few minutes before cutting. That's it.
Same muscle as a filet mignon (the tenderloin, the least-worked muscle on the animal) just cut from the narrower end. It's not uniform enough to plate like a restaurant filet, but it's every bit as tender. From cattle raised on pasture, eating real forage from day one.
Keep frozen until ready to use for up to 12 months. Thaw in the refrigerator overnight, or quick thaw in a bowl of cold water (keep it in the sealed package). Use within 1–2 days of thawing, or refreeze immediately if plans change.