Trim all visible fat (fat won’t dry properly). Freeze until firm but not rock solid—this makes slicing easier. Slice across the grain into thin strips, about ⅛-inch thick. Place strips in a medium bowl with a lid.
In a small bowl, whisk together Worcestershire, soy sauce, tomato sauce, vinegar, sugar, onion, salt, and garlic powder. Pour over beef, cover, and refrigerate at least 8 hours or overnight for best flavor.
Preheat oven to 140°F (or the lowest possible setting). Place beef strips on a cooling rack set over a baking sheet.
Dry in the oven for 18–24 hours, until the jerky is very dry, slightly splintery at the edges, and cracks when bent.
Allow jerky to cool completely. Wrap lightly in plastic wrap or store in an airtight container.
