Melt 1/4 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. 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 350° for 45-50 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes before inverting onto a serving plate. Serve warm.