The procedure begins with the careful inspection of the beans. Take no more than a half cup of beans in a large plate, and remove all the damaged ones. Remember, there should be no stone among the beans.
After that, rinse the beans in a strainer. Use only cool water for this. There are chances that warm water will spoil their taste.
It is the time to turn the burner on. Take a large skillet with at least eight cups of water in it. Add the beans to the water, and set the heat to maximum. Cook the beans for a couple of minutes after they reach a rapid boil. Meanwhile, skim any gray foam that comes to the water surface.
Now lower the heat, and let the beans simmer at least for 20-25 minutes. Meanwhile, add salt, bacon, chillies and mint.
Keep cooking the beans for another 30 minutes until they are tender. Add a little more water, if required. After that, remove the chillies and mint while keeping the beans warm.
Take another pot, and heat one tablespoon of lard. When the oil is hot, add no more than a cup of beans alongside their liquid.
It is the time to use the potato masher. Mash the beans with full force, making sure that there is no whole bean present in the pot.
Fry the mashed beans for a few minutes, and then transfer the material to a large bowl. Add a pinch of salt before garnishing with the Mexican cheese. Repeat the same process with the remaining beans.