Flavored butter:
Leave the butter out of the refrigerator for ½ hour or until it can be worked with a spatula, add the chopped herbs and citrus zest, mix well, place it on greaseproof paper and form a roll. Refrigerate for 40 minutes.
Use the tip of a sharp knife to make small pockets in the meat and stuff them with the garlic cloves.
Once there is a good ember in the grill, make a sort of crown and place the meat fat down on the grill on top of this crown of embers, and salt the meat. The idea is to seal (brown) both sides and once sealed, finish cooking the beef fat down, slightly reducing the heat by spreading the embers a little (20 minutes).
Place a few herb butter medallions on it and allow it to melt.

When the meat is ready, place it on a board and let it rest for about 5 minutes before slicing! This is very important, as the juices will be well distributed and do not get lost on the board.