Cook all ingredients in a heavy saucepan over low heat, stirring constantly until the mixture thickens (the bottom of the pan will be visible as the mixture thickens). Remove from the heat and turn mixture into a buttered heat-proof dish to cool. Shape teaspoon-size amounts into small balls, rolling the mixture in the palms of your hands. Roll the balls in chocolate sprinkles or cocoa and serve. "Brigadeiros" can be kept for up to a week in a sealed container.