Mix the ingredients for the marinade and grate in a mortar. Brush the mayor`s piece with a dash of olive oil and then rub the marinade on the meat. Wrap the meat in cling film and marinate in the refrigerator for 2 hours. Then let it rest for another hour at room temperature.
Briefly bring the ingredients for the glaze to the boil in a small saucepan and then refrigerate.
Since the meat is not cooked over direct heat, divide the grill into 2 zones. Sear the meat on both sides over direct heat, put the thermo in the center of the piece of meat and then place the mayor`s piece on the indirect zone of the grill, i.e. not directly over the embers. Place a drip tray with some liquid underneath. Close the lid of the grill. Brush the meat with the glaze every 15 minutes.
After approx. 1 - 1.25 hours and at 110 ° C - 130 ° C, the meat should have reached a core temperature of 60 ° C and should be removed from the grill. Let the roast rest for another 15 minutes and serve.