In a medium cast iron skillet over medium-high heat, toast the pepitas and sesame seeds until aromatic and lightly browned, 2-4 minutes. Transfer the seeds to a small bowl and return the pan to the heat.
Add the Francese rolls to the pan and toast until charred on both sides, about 5 minutes. Transfer the charred bread to a pan and cover with water. Let soak for 1 hour.
Add the tomatoes, tomatillos, ½ of an onion, pasilla, guajillo, and 1 clove of garlic to the pan and char on all sides, 10-20 minutes. Remove items as they become charred and set aside.
In a medium pot, combine the cubed pork, salt, ½ of an onion, 1 garlic clove, and the water. Bring to a boil, then cover and simmer for 1 hour, or until the pork is tender. Strain the pork from the broth and set both aside.
Squeeze out as much water as possible from the soaked bread, then add to a blender with the toasted seeds, charred vegetables, pepper, and allspice. Blend until smooth. Set aside.
Add the pork lard to a medium bowl and microwave for 2 minutes, until melted. Stir in the annatto paste until smooth. Set aside.
Add the hot, peeled potatoes to a large roasting pan. Mash the potatoes until smooth. Add the melted lard mixture, half the of blended tomatillo sauce, and ½ of the instant corn masa. Mix with your hands until well combined. Season with salt. The mixture should be red and somewhat tacky. If the dough is too dry, add more of the sauce. If too thin, add more corn masa.
To assemble the paches, lay a banana leaf on a clean work surface. Add a bit of potato dough to the center. Place some of the meat in the center, covering with the potato dough. Fold the leaf around the dough, then wrap with a second leaf and a piece of aluminum foil. Repeat with the remaining ingredients.
Layer a base of banana leaves in a large pot and place the wrapped paches on top. Fill the pot halfway with water. Cover the top with more banana leaves and the lid, then steam over medium heat for 1 hour. Remove the paches from the pot and let cool slightly.