Preheat grill to medium or oven to broil on high.
Melt butter over medium heat in a saucepan. Add diced jalapeño and cook for a minute.
In a small bowl combine combine cream cheese, jalapeño, cilantro, lime juice, and garlic salt. Set aside.
In a large bowl, mix ground turkey with garlic salt, minced onion, and Worcestershire sauce.
Lightly spray a foil lined pan with oil. Divide meat into 8 equal portions and flatten portions into 4-inch round patties, pressing lightly against the pan to flatten.
Divide filling into 4 equal portions. Place filling on 4 of the patties and spread to within a ½ inch of the edge.
Cover with remaining 4 patties and pinch the edges closed.
Grill patties over medium heat for 6-7 minutes on each side or until completely cooked. Or broil by placing burgers on a foil lined pan approximately 6″ from the broiler, 5-6 minutes on each side or until completely cooked. Turkey should reach an internal temperature of 165 degrees.
Serve on buns with optional avocado, bacon, lettuce and tomato.