Combine mayonnaise, basil, lemon zest and 1/2 package blueberries in a small bowl; mix well and reserve.
Combine remaining blueberries, garlic, lemon juice and Dijon mustard in a bowl; mash well with a fork. Add ground turkey, bread crumbs, salt and pepper; mix until well combined. Divide into 4 portions and form into 3 1/2-inch diameter patties.
Coat a grill pan with cooking spray and heat over medium-high heat. Add patties and cook 5 to 6 minutes per side or until juices run clear. To serve, place 1 tomato slice, 1 lettuce leaf and a turkey burger on bottom half of each muffin. Spread cut side of muffin tops with basil mayonnaise and place on burgers. Serve immediately.