2-1/2 pounds beef tenderloin, cut into 1-inch cubes
2-1/2 pounds pork tenderloin, cut into 1-inch cubes
1 cup sour cream
3 tablespoons prepared horseradish
1 tablespoon chopped onion
1 teaspoon white vinegar
1/2 teaspoon salt
1/4 teaspoon pepper
1 can (8 ounces) tomato sauce
1/3 cup steak sauce
2 tablespoons brown sugar
6 to 9 cups peanut or canola oil
In a 1-cup measure, combine soy sauce, Worcestershire sauce and garlic. Divide mixture between two large resealable plastic bags. Add beef to one bag; add pork to the second bag. Seal bags and turn to coat; refrigerate for 4 hours, turning occasionally.
Meanwhile, in a small bowl, combine the horseradish sauce ingredients. In another bowl, combine the tomato sauce, steak sauce and brown sugar. Cover and refrigerate sauces until serving.
Drain meat and discard marinade. Pat meat dry with paper towels. Using one fondue pot for every six people, heat 2-3 cups oil in each pot to 375°. With fondue forks, cook meat in oil until it reaches desired doneness. Serve with sauces.