Rinse the pinto beans under cold water and remove any debris or stones.

In a large pot, combine beans, water, onion, and garlic. Bring to a boil, then reduce heat to low and simmer for 2 hours or until beans are very tender. Add salt during the last 30 minutes of cooking.

Drain the beans, reserving 1/2 cup of the cooking liquid. Remove and discard the onion quarters.

Heat lard or oil in a large skillet over medium heat. Add the minced garlic and cook for 30 seconds until fragrant.

Add the cooked beans to the skillet. Mash them with a potato masher or the back of a wooden spoon.

Gradually add the reserved bean cooking liquid until you reach your desired consistency. Cook for 5-10 minutes, stirring frequently, until the beans are creamy and well combined.

Taste and adjust seasoning with additional salt if needed. Serve hot.