In a 4-quart saucepan simmer beans, ham hock, yellow onion, garlic, cumin, water, and broth, partially covered, until beans are tender, about 1 hour. (Old beans may take longer to cook.)
Step 2
Transfer ham hock to a work surface and cool until it can be handled.
Step 3
Cut away ham and chop fine, discarding bone and fat.
Step 4
Transfer 1 1/2 cups each beans and cooking liquid to a blender and let cool slightly.
Step 5
Purée mixture (use caution when blending hot liquids) and return to pan.
Step 6
Stir in ham, vinegar, sugar, and salt and pepper to taste and heat until hot.
