1. Bring first 8 ingredients, 1/4 tsp. salt, and, if desired, serrano chile to a boil over medium-high heat in a Dutch oven. Cover and cook, stirring occasionally, over medium-low heat 3 hours or until beans are tender. Stir in remaining 1 tsp. salt. Remove and discard salt pork and chile before serving.
Refritos: Cook 4 cups Traditional Frijoles in 1 Tbsp. hot vegetable oil in a large skillet over medium heat. Reduce heat, and mash beans with a potato masher as they cook, adding water if necessary to keep moist. Simmer, stirring often, 10 minutes. Prep: 5 min., Cook: 10 min. Makes 6 to 8 servings.