Rinse the pork thoroughly and dry with napkins. Peel the garlic and cut into small slices.
Prepare the marinade: mix mayonnaise, salt, pepper and mustard. Brush the marinade over the meat and leave in the refrigerator for at least an hour and a half.
When the meat is soaked, make holes on its surface with the tip of a knife and stuff it with garlic. Wrap the meat in foil and place in a baking dish.
Bake in the oven at 180C for an hour, then carefully unwrap the foil and bake for another 15 minutes until golden brown.
Cut the finished meat into slices. You can serve it either hot or cold. With bread croutons and meat sauces.