Burnt-Sugar Cake
["1 3/4 c. sugar", "3/4 c. boiling water", "2/3 c. soft butter", "1 tsp. vanilla", "2 eggs, separated", "3 c. sifted cake flour", "3 tsp. baking powder", "1/2 tsp. salt", "3/4 c. milk"]
["In a small heavy skillet, heat 3/4 cup sugar, stirring until a brown syrup forms and mixture begins to smoke. VERY GRADUALLY (because of spattering), stir in boiling water and remove from heat. Cool thoroughly."]
["sugar", "boiling water", "butter", "vanilla", "eggs", "cake flour", "baking powder", "salt", "milk"]