1. Combine ground beef, onion, jalapeņo, cilantro and 1/4 c. cheese in medium bowl, mixing lightly but thoroughly. Lightly shape into four 1/2-in. thick patties. 2. Heat large nonstick skillet over medium heat until hot. Place patties in skillet; cook 10-12 min. to medium (160°F) doneness, until not pink in center and juices show no pink color, turning occasionally. About 3 min. before burgers are done, top evenly with remaining 1/4 c. cheese. 3. Place burgers in tortillas or buns; season with salt and black pepper, as desired. Top with desired toppings.
* Cook's Tip: To charcoal grill, place patties on grid over medium, ash-covered coals. Grill, uncovered, 11-13 min. to medium (160°F) doneness, until not pink in center and juices show no pink color, turning occasionally.
* Cook's Tip: To gas grill, preheat grill according to manufacturer's directions for medium heat. Grill patties, covered, 7-8 min. to medium (160°F) doneness, until not pink in center and juices show no pink color, turning occasionally.