Preheat oven to 350 degrees.  In a mixing bowl; combine mangoes and lemon juice; set aside.  You can either do this next step in the oven, or on a stove top.  In an 8-inch baking pan; melt ¼ cup of butter and sugar; stirring until sugar dissolves.  Arrange mangoes decoratively in pan.  In a mixing bowl; combine egg, oil and buttermilk.  Stir in remaining ingredients.  Pour batter over mangoes; bake 35-40 minutes.  Invert onto serving platter.  In a saucepan over medium heat; warm preserves.  Brush over top of cake; allow to sit 10 minutes.