Heat a large skillet over medium heat and cook the pork belly or bacon until crispy. Remove and set aside.
In the same skillet, add the chopped onion, garlic, and bell pepper. Sauté until softened.
Add the chicken or beef chunks, and cook until browned on all sides.
Stir in the tomatoes, ground cumin, paprika, dried oregano, salt, and black pepper.
Simmer for 20-30 minutes, or until the meat is cooked through and tender. Set aside.
In a large bowl, combine the masa harina, baking powder, and salt.
Gradually mix in the vegetable oil or lard until the mixture resembles coarse crumbs.
Slowly add the chicken broth, mixing until a smooth dough forms. The masa should be moist but not too sticky.
Drain and pat dry the soaked corn husks. Lay out one husk on a flat surface.
Spread a spoonful of masa dough in the center of the husk, leaving space on the sides and bottom.
Add a portion of the filling on top of the masa.
Optionally, add sliced olives, diced red chili peppers, or a spoonful of cooked rice.
Fold the sides of the husk over the masa and filling, then fold the bottom of the husk up to enclose the tamale.
Arrange the tamales upright in a large steamer or pot. You can place a few crumpled pieces of husk or a heatproof cloth under the tamales to keep them from sticking.
Cover the tamales with a damp cloth or additional husks.
Steam over medium heat for 1 to 1.5 hours, or until the masa is fully cooked and pulls away from the husks easily.
Remove the tamales from the steamer and let them cool slightly.
Enjoy your meal!