Preparation

• Cut the steak into one-inch cubes and put them in a mixing bowl. Add the lemon grass and lemon rind. Put the onion, soy sauce, oil, shrimp paste, cumin, coriander, turmeric, salt and sugar in the container of a food processor or blender, and blend to a fine paste.
  Pour this over the meat and blend well. Let stand one hour. Light and heat the grill.
  
  Arrange equal portions of the meat on each of eight wooden skewers that have been pre soaked in cold water. Place the meat on the grill and cook about two minutes.
  Turn and cook about two minutes on the other side. Serve with peanut sauce.
  
  The sauce:
  Heat the oil in a saucepan, and add the garlic and onion. Cook stirring over low heat for 2 to 3 minutes.
  Add the pepper flakes. Ginger, shrimp paste, tamarind liquid, sugar, peanut butter, and lemon or lime.
  Whisk in the boiling water. When blended, remove from heat.
  If the sauce starts to curdle, add a little more water.