Rinse the dry pinto beans well and be sure there are no rocks. Place the clean beans in a large pot and cover with about an inch of water. Do NOT add any salt at this point. Bring to a full boil, turn off the heat, cover, and let set for 2 hours.

Drain the beans. Rinse well with cold water and drain them again.

Add the chicken broth, salt, bay leaves, and oregano to the drained beans. Bring them to a boil, reduce the heat to low, cover, and allow to simmer for 45 minutes.

While the beans simmer, prepare the remaining ingredients. Heat a large skillet over medium high heat and cook the bacon until it is browned and the fat renders.

Add the onion, garlic, and serrano pepper. Cook for 2 minutes, scraping the bottom the pan with a wooden spoon as the aromatics cook.

Add the two cans of tomatoes and the juice from the tomatoes. Bring the mixture to a gentle boil and allow it to thicken.

Add the bacon mixture to the beans and increase the heat to medium high. Allow the beans to finish cooking and the sauce to thicken. This takes about 20-30 minutes. You can also use a potato masher to mash some of the mixture to thicken it faster.

Add the cilantro and serve.