1. Put beans, stock, bay leaves, onion, jalapeno, cumin, and 1/2 teaspoon salt into a medium saucepan. Bring to a boil. Reduce to a brisk simmer. Cook 15 minutes, stirring occasionally. Strain, reserving 1/2 cup cooking liquid; discard onion, jalapeno, and bay leaves.

2. Return beans and reserved cooking liquid to pan, and stir in 2 tablespoons cheese. Mash slightly with a potato masher until about half of the beans are broken down, leaving remaining beans whole. Season with salt, if desired. Cover with foil until ready to serve. Serve warm, sprinkled with remaining 2 tablespoons cheese.