Preheat oven to 450. Prepare a baking sheet with cooking spray; set aside. To prepare crust, combine baking mix, 1/3 cup mayonnaise and milk in a mixing bowl. Mix until soft dough forms. If dough is too sticky, add additional baking mix as needed. Press dough into 12x8-inch rectangle onto baking sheet. Bake for eight minutes or until golden brown. To prepare topping, combine turkey, onions, bacon and remaining mayonnaise. Spoon over crust to within 1/4" of edges. Sprinkle top evenly with cheese. Bake six minutes or until mixture is hot and cheese is melted.