Stuffed Border Burgers

1 1/2 lbs. lean ground beef
2 Tbsp. ketchup
1/2 c. finely chopped onion
1 (4.25 oz) can chopped ripe olives, drained
1 Tbsp. taco seasoning
6 (1 oz) slices Monterey Jack cheese/peppers
6 onion rolls, split and toasted

Preheat grill or grill pan to medium-high heat. In large bowl combine beef, onion, olives, ketchup and taco seasoning. Shape mixture into 12 (4-inch) patties. Fold cheese slices into quarters; place cheese in center of each of six patties. Top with remaining six patties, pressing to seal edges. Grill four to five minutes on each side or until done. Serve on rolls. Note: Shredded lettuce, sliced tomatoes and guacamole make great toppings for these burgers. Or make a sauce by stirring together 1/2 cup sour cream, 1/3 cup ketchup, 1 (4.5 oz.) can chopped green chiles and one tablespoon minced fresh cilantro. Cover and chill sauce in refrigerator until ready to serve. Serves six.