Thoroughly wash the banana leaves under running water and pat them dry with a cloth. Divide the leaves into three sections based on their size. The largest ones will be used to hold the dough, the medium-sized ones will serve as lining, and the narrowest ones will be used as ribbons.
Once the leaves are ready, lay them out on a large work surface along with the rest of the ingredients, each in separate containers: the filling, the garnishes, the dough balls, and the annatto oil.
Place a large banana leaf on the work surface, lightly oil your fingers with annatto oil, and place a dough ball on top. Flatten the dough ball with your fingers, spreading it out until it forms a circle about 3 mm (1/10th of an inch) thick.
Spoon three large tablespoons of filling onto the center of the dough circle, then add a slice of onion, a slice of bell pepper, two capers, an olive and two raisins on top of the filling.
Lift both ends of the leaf, one in each hand, and gently join them together, suspending the hallaca over its own weight so that the filling remains in the center. Carefully roll the hallaca until it is tightly wrapped.
Fold back the two ends of the leaf, then cover the hallaca with a ribbon, wrapping it and securing the two ends of the leaves in the opposite direction.
Finally, place another ribbon around the hallaca like a belt and tie it with twine, making three loops in both directions.
Repeat the process with the remaining dough and filling until all the hallacas are assembled.
To cook the hallacas, fill a large pot with water and bring it to a boil. Carefully place the hallacas in the pot and cook for about 1 1/2 to 2 hours, or until the dough is firm and cooked through.
Once cooked, remove the hallacas from the pot and let them cool slightly before serving. Hallacas can be refrigerated for up to a week.