Preheat oven to 350degrees. If desired, in a small bowl, combine peaches and bourbon; toss to coat. Let stand 10 minutes., Meanwhile, place 1/4 cup butter in a 10-in. ovenproof skillet; heat in oven 5-7 minutes or until butter is melted. Sprinkle brown sugar evenly over butter. Arrange peach slices over brown sugar., For batter, in a large bowl, cream butter and sugar until light and fluffy. Beat in egg and vanilla. In another bowl, whisk flour, baking powder and salt; add to creamed mixture alternately with milk, beating after each addition just until combined. Spread batter evenly over peaches., Bake 40-45 minutes or until a toothpick inserted in center comes out clean. Cool 5 minutes before inverting onto a serving plate. Serve warm.,