Anita's Sloppy Joes (with secret ingredient)

Courtesy of Anita Apple:

Spicy Cocoa Sloppy Joes
Ingredients:
€ 1-1/2 pounds lean ground beef
€ 1 to 1-1/4 cups chopped onion
€ 1 cup ketchup
€ 2 tablespoons HERSHEY'S Cocoa
€ 1-1/2 tablespoons yellow mustard
€ 2-1/2 teaspoons chili powder
€ 1-1/2 teaspoons ground black pepper
€ 1-1/4 teaspoons salt

Directions:
1. Cook ground beef and onion in large skillet on medium heat until beef is
browned and onion is tender. Drain excess fat.

2. Stir in ketchup, cocoa, mustard, chili powder, pepper and salt. Heat 10
to 15 minutes on low heat or until hot. Serve in buns. Cover; refrigerate
leftovers. About 4-1/2 cups sandwich filling.