Trim all visible fat from the beef and place in freezer for an hour or two to partially freeze.

While the meat is in the freezer, combine the worcestershire sauce, garlic powder, brown sugar, smoked paprika, red pepper flakes, diced Serrano peppers, and red wine vinegar in a bowl or ziplock bag and mix well. Or skip the freezing phase and use a Jerky Slicer for even sliced strips.

Remove the meat from the freezer and slice ¼" strips against the grain. Cut with the grain for more chew.

Add sliced beef to the mixture in a ziplock bag or bowl and marinate for 8-24 hours in the refrigerator.

After the meat has finished marinating, remove from refrigerator and strain excess marinade and pat dry the beef strips with paper towels

Dry with your favorite jerky making method. I used my dehydrator and dried for 5 hours at 160 degrees.

The jerky is finished when it bends and cracks, but does not break in half.