Rinse and drain 2 cups cooked black beans, reserving 1/2 cup cooking liquid or water
Heat 2 tablespoons oil or lard in a skillet over medium heat
Add 1/2 small chopped onion and cook until soft
Add 2 minced garlic cloves and cook for 30 seconds
Add the black beans, 1/2 teaspoon salt, and 1/2 teaspoon ground cumin
Mash the beans with a potato masher or spoon
Stir in reserved liquid a little at a time until desired texture is reached
Cook, stirring often, until thick and creamy
Taste and adjust salt
Serve warm