Heat gas grill to 500º. Divide meat into ½ lb. portions, forming into a ball. Flatten each ball into a ¾ inch thick patty. Make a small indentation in the middle of each patty about ½ inch in diameter. Sprinkle each side of burger patties evenly with ½ tsp of seasoning.
Cook patties on heated grill, with lid shut, for 5 minutes on each side. Note: Only flip once and never press down on the top of your burger to check for doneness… you will lose all the juices.
Remove burgers from grill and cover with foil. Grill buns until heated and browned; this step is very important; it adds texture and will help prevent your burger from becoming soggy. Once buns are nicely toasted, remove from heat and spread 1 TBSP of Secret Sauce on each side. Add grilled lamb burger and serve immediately.
Secret Sauce aka Parmesan-Oregano Aioli
Mix together mayonnaise, parmesan, oregano, Dijon and horseradish in a small bowl. Refrigerate until ready to use. You will have extra sauce to serve on the side.