From Mary Jo Tolbert's recipes.
Mix 1 cup light brown sugar and 1/2 cup minus 1 T. of granulated white sugar with 1/3 cup hot water in saucepan. Stir over low heat until sugar dissolves. Boil rapidly until syrup spins a thread (240°). In a large bowl, beat 2 egg whites until foamy, add 1 T. sugar, then continue to beat until stiff peaks form. Slowly pour syrup into beaten egg whites, beating constantly. (In a stand mixer) Add 1 t. vanilla and 1/8 t. salt. Continue beating until peaks are formed. Spread over cake.