Beef Bulgogi Burgers

Name: Beef Bulgogi Burgers
Prep time: 20 min
Cook time: 10 min
Total time: 30 min
Cuisine: Asian, Korean
Ingredients: 3 tablespoons soy sauce; 1 tablespoon Asian/toasted sesame oil; 1½ tablespoons (packed) dark brown sugar; ¼ teaspoon crushed red pepper flakes; ¼ teaspoon ground ginger; 2 cloves garlic, (minced); 1 slice white or whole wheat sandwich bread, (crusts removed and torn into ¼-inch (6-mm) pieces); 1½ pounds 85% lean ground beef; ½ cup chopped scallions, (from 4 to 5 scallions); 5 hamburger buns; Lettuce leaves, (for serving (optional)); ¾ cup mayonnaise, (best quality such as Hellmann's or Duke's); ¼ cup Asian chili sauce, (such as Sambal Oelek (available in Asian aisle of most supermarkets)); ¼ teaspoon granulated sugar