Crush the garlic along with the dry spices until the mix becomes almost a paste. Add the onion chopped or sliced into thin rings and the Seville orange or grapefruit juice.
Coat the piglet in this marinade, preferably on the inside. Pierce with a knife in several places to allow the seasoning to go in deeply.
Bake at medium temperature (350ºF o 176ºC).
In an outdoor grill, the piglet is always placed with the chest up, but almost at the end it is turned to be evenly roasted.