Spicy steamed pork knuckle with preserved mustard greens

Method

1. Boil the elbow in clean water for 30 minutes
2. Stir-fry the preserved mustard greens with a little oil
3. Put the pork knuckles and preserved mustard greens in a large bowl and add the chili powder with the prepared sauce
4. Put it in a pressure cooker and steam under high pressure for 70 minutes until soft and tender