1. Place the tripe in a deep pot filled with enough cold water to cover it and boil for 2 hours.
2. In a blender, combine all the other ingredients except butter, and process into a fine, smooth mixture.
3. Drain the tripe and return it to the pot. Add the yoghurt mixture and bring to a boil. Lower the heat and simmer for 15 minutes or until the sauce has thickened. Add butter, stir through and season to taste.
4. Serve with steamed bread.