Place the duck on a rack in a roasting tin. Rub the crushed garlic and pepper under the skin of the duck. Rub the skin with 1 sachet sazon seasoning.
Roast 3 hours in the preheated oven, to an internal temperature of 80 degrees C.
Place the reserved duck innards and 1 sachet sazon seasoning in a saucepan with enough water to cover. Bring to the boil, reduce heat and simmer 30 minutes, until tender.
Place the rice mix in a medium saucepan with just enough water to cover. Mix in the oil and 1 sachet sazon seasoning. Bring to the boil. Reduce heat, cover and simmer 25 minutes, stirring occasionally.
In a bowl, mix the cooked innards, cooked rice and croutons. Stuff the cooked duck with the mixture to serve.
Sazón seasoning can be found online or in some Caribbean or specialty shops. A well known brand is Goya.