Hello Claire! Making steak tartare at home is a wonderful culinary project, and choosing the right cut is indeed the most critical step for both texture and safety.
The gold standard for steak tartare is beef tenderloin (also known as filet mignon). Tenderloin is ideal because it is naturally very lean, exceptionally tender, and contains almost no tough connective tissue or gristle. If tenderloin is out of your budget, high-grade top sirloin is a good alternative, though tenderloin will consistently give you the silkiest, most luxurious texture.
Here are a few essential rules to follow when buying and handling meat for tartare:
1. Never use pre-packaged ground beef. Ground beef exposes all surface bacteria to the interior and sits in packaging for days. You must always purchase a whole-muscle steak and mince it yourself by hand.
2. Buy the freshest cut possible. Rather than picking a pre-wrapped styrofoam tray from the open refrigerated aisle, visit the meat counter and ask the butcher for a fresh, whole piece cut from the center of the loin.
3. Trim the outer layer. Bacteria on whole cuts of beef live on the exterior surface. For an extra layer of safety, use a clean knife to trim away a very thin layer of the exposed outer surface before dicing the interior meat.
4. Keep everything cold. Place your beef in the freezer for about 15 to 20 minutes before cutting. This firms up the meat so you can dice it into clean, tiny cubes with a sharp knife instead of tearing or mashing it. It is also good practice to mix your tartare in a bowl set over another bowl filled with ice.
Take your time with the prep work and enjoy the process!