Beef satay

Name: Beef satay
Ingredients: 1 kilogram blade or rump steak; 1 tablespoon ground cumin seed; 1/2 teaspoon ground saffron; 1 tablespoon coriander; 1 teaspoon salt; 1 tablespoon brown sugar; 3 clove garlic, crushed; 3 teaspoon ground ginger; melted butter or oil; 4 tablespoon crunchy peanut butter; 2 teaspoon vinegar (or 1½ tablespoons tomato sauce); 1 lemon, juice of; 1 teaspoon brown sugar; 1 1/2 tablespoon boiling water