Ingredients:
2 pounds beef or buffalo sirloin, trimmed of fat and sinew
1/4 cup soy sauce
3 tablespoons brown sugar
3 cloves garlic, peeled and smashed
2 tablespoons Worcestershire sauce
1 tablespoon liquid smoke
2 teaspoons red pepper flakes
2 teaspoons onion powder
2 teaspoons chili powder
1 teaspoon salt
1 teaspoon freshly ground black pepper

Method:
Slice the meat into strips against the grain, 1/4-inch thick and 1-inch wide. (If necessary, freeze the meat for up to 2 hours to facilitate slicing.)

In a large, wide bowl, combine the remaining ingredients. Place the meat in the marinade, cover, and refrigerate to marinate overnight, turning occasionally.

Preheat the oven to its lowest setting, between 145 and 150 degrees F.

Line 2 large baking sheets with foil and top with 2 heavy wire racks. Drain the meat, pat dry, and arrange evenly on the racks without touching. Place in the oven, leaving the oven door open a crack for air circulation. Leave in the oven until dry, but still firm (not spongy or brittle), 10 to 12 hours, depending upon the thickness of the meat, turning once or twice during the process.

Remove from the oven and store in waxed paper at room temperature for up to 2 days. Wrap in plastic and refrigerate to store for up to 1 week, or place in a mason jar and keep in a cool dry place for 1 to 2 weeks.