Brown 1 stick butter in heavy, 4-quart saucepan. Add 2 cups brown sugar; cook together a few minutes. Now add 2 cups water and 3/4 teaspoon salt; bring to a boil. Add 1 3/4 cups baby pearl tapioca; cook until clear, stirring frequently. Chill. Add 1 teaspoon vanilla and whipped cream, enough to taste.