Preheat oven at 350 degrees.
Blanch and peel 8 ripe peaches. Cut in halves. Or use canned or frozen peaches. Slice 1 inch thick.
Butter a 9-by 1 1/2-inch round cake pan with 3 tablespoons soft butter, and sprinkle with 1/2 c. sugar over butter. Arrange peaches close together in a circle in the pan.
In an electric mixer, cream 3/4 stick (6 tablespoons) soft butter with 1/2 cup sugar. Beat in 1 egg, and 1 teaspoon vanilla.
Sift together 1 1/4 cup cake flour, 1 1/2 teaspoons baking powder, and a pinch salt and combine into butter sugar mixture.
Gradually stir in flour batter over peaches, smoothing top.
Bake cake 55 minutes to 1 hour, or till brown.
Cool on rack for 10 min.
Invert on a platter. Brush peaches with melted apricot glaze or strained strawberry jam. Serve with whipped cream.