Partially freeze the beef for 1-2 hours to make it easier to slice.

Slice the meat against the grain into strips between 1/8 and 1/4 inch thick.

In a medium bowl, whisk together the brown sugar, soy sauce, Worcestershire sauce, smoked paprika, meat tenderizer, black pepper, red pepper flakes, onion powder, and garlic powder until the sugar is dissolved.

Place the beef strips in a large ziplock bag or container and pour the marinade over them. Ensure all pieces are evenly coated.

Refrigerate and marinate for at least 12 hours or overnight, turning the bag occasionally to ensure even distribution.

Preheat your oven to 175°F (80°C) and set two oven racks in the centermost positions.

Line two baking sheets with aluminum foil and place wire racks on top.

Remove the beef from the marinade, allowing excess to drip off, and arrange the strips in a single layer on the wire racks.

Bake for 3-4 hours, rotating the pans from front to back and top to bottom halfway through.

To test for doneness, remove a piece and let it cool to room temperature. It should be dry to the touch, leather-like in appearance, and chewy but still somewhat tender.