Partially freeze the beef for 30–45 minutes for easier slicing.
Slice the beef into thin strips against the grain.
In a bowl, combine soy sauce, Worcestershire, brown sugar, garlic powder, onion powder, and red pepper flakes.
Add the beef strips and marinate overnight in the fridge.
Preheat oven to 170°F (or use a dehydrator).
Arrange the beef in a single layer on a wire rack over a baking sheet.
Pat dry lightly with paper towels to remove excess marinade.
Bake for 4–6 hours, flipping halfway, until firm but still slightly pliable.
Cool completely before storing.
Notes
For a richer glaze, brush lightly with maple syrup during the last 30 minutes of drying.Adjust spice level by adding or reducing red pepper flakes.Store in airtight container for up to 3 weeks in the fridge or 3 months in the freezer.