In a large mixing bowl, combine soy sauce, Worcestershire sauce, brown sugar, onion powder, garlic powder, paprika, pepper, and red pepper flakes.
Place the sliced beef strips into a resealable bag or shallow dish and pour the marinade over the meat.
Seal and refrigerate for 12–24 hours, turning occasionally to ensure even marinating.
Remove the beef from the marinade and pat dry with paper towels.
Place beef strips in a single layer in a dehydrator or on a wire rack in a 175°F (80°C) oven.
Dehydrate for 4–5 hours or until the jerky is dry and bends without snapping.
Let cool completely before storing in an airtight container.
