Separate corn husks. Fill a large bin or sink with water and submerge corn husks. Allow to soak until pliable, about 15 minutes.
Remove from water and allow excess water to drain off
Place lard, onion and a pinch of salt into shallow pan over low heat on the stove. Heat until lard is melted and onion starts to turn translucent, ~ 5 minutes
Discard the onion from the lard and remove the pan from the heat. Allow the lard to cool slightly.
In a large bowl, place the masa, black beans, lard and salt
Mix ingredients by hand until combined and all ingredients are thoroughly incorporated. The masa will be sticky. It takes me about 10-15 minutes mixing by hand to incorporate the ingredients.
Taste the masa for salt and add if necessary. See notes on salt.
Using a spoon, place ~1/3 cup masa mixture into the curved part of the corn husk and extend 1/2 to 2/3 upwards towards the pointed ends. You will want to leave about 1/2-1 inch gap between the bottom of the corn husk and the masa mixture. Place a strip of cheese on top of the masa mixture, if using. See photos for reference and notes on husks.
Fold the sides over and the pointed top part downwards toward the curved part of the husk to create a packet. See photos for reference.
Repeat previous 2 steps until all of the masa is gone.
Place water in the bottom of a tamalera or pot fitted with a steamer basket. Heat over high heat to a boil. Reduce heat to medium-low. See notes.
Place the tamales standing upright with the folded part of the tamal towards the bottom of the pot. Or, lay the tamales flat, overlapping in layers if there is not room for them to stand upright.
Cover the pot and allow the tamales to steam for 1-2 hours or until the masa is cooked through. See notes.
Enjoy these warm, with the husks removed. You can top these with a salsa of your choice or Mexican cream and shredded cheese.