In a bowl, combine the minced garlic, ground cumin, paprika, annatto powder, vegetable oil, vinegar, soy sauce, oregano, black pepper, and salt. Mix well to create a paste.
Rub the marinade all over the pork leg, ensuring it is well-coated. Cover and refrigerate for at least 4 hours or overnight for best results.
Preheat your oven to 325°F (165°C).
Place the marinated pork leg in a roasting pan.
Arrange the chopped onion and bell pepper around the pork.
Pour the beer or water, orange juice, and lime juice into the pan.
Cover the roasting pan with aluminum foil.
Roast in the preheated oven for about 3 to 4 hours, or until the pork is tender and the internal temperature reaches 160°F (71°C).
Remove the foil and increase the oven temperature to 400°F (200°C).
Roast the pork for an additional 20-30 minutes, or until the skin is crispy and golden brown.
Let the pork rest for 15 minutes before carving.
Enjoy your meal!