Melt ¼ cup butter; pour into an ungreased 9-in. round baking pan. Sprinkle with brown sugar.
Arrange peach slices in single layer over sugar.
In a large bowl, cream sugar and remaining butter until light and fluffy, 5-7 minutes. Beat in egg and vanilla.
Combine the flour, baking powder and salt; add to creamed mixture alternately with milk, beating well after each addition.
Spoon over peaches.
Bake at 180° for about 45 minutes.
Cool for 10 minutes before inverting onto a serving plate.
