Place chicken, onion, chicken bouillon, salt, and bay leaves in the crockpot.
Fill with 2 cups water and cook on high for 2 1/2 hours. (This can also be cooked on the stovetop in a large pot for 45 minutes.)
Once cooked, remove & shred chicken and set aside.
Reserve chicken broth for later.
Put 12 green chiles in a blender, along with 3 garlic cloves, cumin, salt, and water.
Blend just long enough until you have a smooth sauce.
Heat skillet over the stove with approx. 1 Tbsp. oil in it.
Pour chile sauce into the skillet and cook approx. 5 minutes, (Mix in a can of cream of mushroom if desired).
Add shredded chicken to chile sauce, lower heat, and let simmer for 10 minutes.
Take off the stove and set it aside. (Refrigerate if necessary.)
Soak corn husks in hot water for approx. 2 hours, so they become clean and more pliable.
Prepare masa by first creaming 2 cups of lard in a stand mixer.
This will take approx. 10-15 minutes with mixer set to medium-high.
In a separate large bowl, mix together Maseca corn flour, baking powder, and salt.
When lard appears fluffy, you can begin to add cornflour mixture to the lard a little at a time and continue to mix.
Begin adding chicken broth a little at a time as well.
Your masa will need between 4 - 5 cups of chicken broth to get the right consistency.
Continue to mix another 15 minutes. To test masa, take a tiny piece of it and drop it in a glass of water.
It should float back to the top.
If not, try adding a little more chicken broth and continue to mix.
To begin making tamales, place water in the bottom of a large steam pot.
Spread masa on the soft side of corn husk from halfway point down to the end.
Place approx. 2 Tbsp. chicken chile mixture on top, add a slice of cheese and fold husk over, first on sides, then fold over the bottom.
Place in steam pot and continue to make other tamales until all masa is used up.
Cover pot and place on stove over medium heat.
Once it begins to steam, set the timer to 2 hours.
Monitor to make sure water in the steam pot does not dry out.
If you need to add water, pour carefully along the sides of the pot, and avoid getting water inside tamales.