2 T vegetable oil or bacon or chorizo (Mexican spiced sausage) drippings
1 medium white onion, chopped
4 garlic cloves, peeled and finely chopped
4 cups undrained cooked beans (most any variety is fine), preferably slightly warm for easy
   mashing
salt if necessary
1/2 cup salted farmer's cheese, crumbled feta or Parmesan, for garnish
Handful of tortilla chips, for garnish

In a large (10-12 inch), well seasoned or nonstick skillet, heat the oil or pork fat over medium heat.  Add the onion and cook, stirring frequently, until deep golden, about 10 minutes.  Stir in the garlic, cook for a minute or so, then use a slotted spoon to scoop in about 1/4 of the beans, leaving most of the liquid behind.  With a bean or potato masher, or the back of a large spoon, mash the beans into a course puree.  Add another portion of the beans, mash them in and continue until all of the beans have been added and coarsely mashed.

Add about a cup of bean liquid (or water) and stir frequently over the heat until the beans are still a little soupier than you'd like to serve them (they'll thicken as they sit).  The total cooking and mashing will take about 15 minutes.  Taste and season with salt, if necessary.

Spoon onto warm serving platter (or individual plates) and sprinkle with the crumbled cheese, decorate with tortilla chips.

Notes:  This is one of many varieties of frijoles refritos.  The "re" in Spanish means "well" or "intensely", not "again and again."

Whether you choose oil or pork fat is up to you, but this is one place where the pork fat makes a significant taste difference.

from Rick Bayless's Mexican Kitchen