Prepare the masa: In a large bowl, mix masa harina with melted lard, sour orange juice (or lime juice), achiote paste, salt, and chicken stock until you achieve a spreadable consistency. Set aside.

Marinate the pork: Cut pork shoulder into 2-inch chunks. Season with garlic, cumin, oregano, salt, pepper, and sour orange juice. Let marinate for at least 2 hours or overnight.

Prepare the rice: Rinse white rice and mix with a bit of achiote oil, salt, and cumin. Do not cook the rice; it will steam inside the nacatamal.

Prep vegetables: Slice bell peppers into strips, cut potatoes into wedges, slice onions and tomatoes into rings.

Prepare banana leaves: Pass banana leaves briefly over an open flame or hot burner to make them pliable. Cut into 12-inch squares.

Assemble nacatamales: Place two banana leaf squares in a cross pattern. Spread 3/4 cup masa in the center into an 8-inch circle. Layer with 2 tablespoons uncooked rice, one piece of marinated pork, potato wedges, bell pepper strips, onion rings, tomato slices, and a mint sprig.

Fold the banana leaves: Bring opposite sides together over filling, then fold in the other sides to create a neat rectangular package. Tie with kitchen twine.

Steam: Place nacatamales in a large steamer or stockpot with a steamer insert. Add water below the steamer level. Cover tightly and steam for 3 hours, checking water level occasionally.

Test for doneness: Unwrap one nacatamal; the masa should be firm and pull away from the leaves easily.

Serve hot: Let rest for 5 minutes before serving. Traditionally served with strong coffee or fresh fruit juice.