Mushrooms add meaty flavor and moisture to the turkey

In a medium skillet heat oil until very hot. Add mushrooms. Cook 2 minutes, stirring occasionally. Add garlic; cook 8 to 10 Minutes until lightly browned and liquid has evaporated. Stir in scallions and 1/2 teaspoon each salt and pepper. Set aside and let cool.
In a mixing bowl, gently mix together turkey, soy sauce, ¾ teaspoon pepper and. Using 1/3 cup of mixture, shape into eight 4 ½” patties approximately 3/8” thick.
Preheat your grill until hot. Turn down the burners to medium. Mound ¼ cup filing in the center of 4 patties. Cover with remaining patties. Seal edges by pressing firmly with fingers. Gently press center to flatten the burger slightly.
Preheat grill on high. Reduce heat to medium and gently place burgers on the rack. On a charcoal grill place the burgers 4 to 6 inches from coals. Cover grill. Grill 8 to 10 Minutes minutes or until cooked through and no longer pink in the center.
Whisk together mayonnaise, soy sauce and mustard. Place buns on grill; grill 1 Minute or until lightly toasted. Spread each bun with 2 tablespoons mayonnaise. Top with burgers and a tomato slice.
