Heat up the iron skillet. Melt butter. Add the brown sugar and 1/4 tsp salt. Break it apart and stir until the sugar dissolves. Set it aside and let it cool.
Peel the peaches and slice. Discard the pits. Arrange on top of the butter & sugar mixture pan. Use as much sliced peaches to form a flower. Set it aside once assembled. Preheat the oven to 350°
In a bowl, combine flour, baking powder and the remaining 1/4 tsp salt.
Mix the cake batter. Cream butter and sugar together. Beat in egg and vanilla extract. Alternately add the flour mixture and milk gradually in the mixing bowl and continue to beat them together until well-blended.
Pour the cake batter on top of the peaches pan. Gently spread the batter on top.
Bake it in the oven for 40-45 minutes or until the toothpick comes out clean when testing.