In a large bowl, combine turkey, pesto and salt. Mix well until pesto is completely mixed in. Shake the gelatin evenly on top of the meat mixture and then mix well. Divide into 6 even patties, about 1/2 cup mixture each.
Place on a sheet tray lines with parchment paper and make the burgers. Roll into a ball and then press into a 5 inch circle, about 1/2 inch thick. Press the center in slightly to make a little indentation. This will help it be flat at the end instead of raised in the center.
Grill immediately or store in the fridge until ready. Make sure to remove them 30-60 minutes before cooking which helps them cook evenly.
Serve on lettuce, topped with a tomato. The sauce is just left over pesto and mayo mixed together.
In baking: preheat the oven to 375° and bake the burgers for 20 minutes.