I happen to be a big fan of upside-down cakes, but an even bigger fan of peaches!! This cake is quite awesome for fellow peach-lovers. You can serve this warm or at room temperature with vanilla ice cream.
Heat oven to 350 degrees. Butter 10-inch round cake pan.
Make topping: Place pecans in small baking pan and toast in oven until fragrant, about 10 minutes. Let cool.
Melt butter in small saucepan over medium-high heat. Stir in brown sugar, corn syrup, and bourbon. Heat to boiling and boil, stirring constantly, until thickened to consistency of syrup, about 5 minutes. Pour into prepared pan. Cut peaches into 1/2-inch-thick slices and arrange in concentric circles on syrup. Arrange pecans decoratively between peaches.
Make cake batter: Sift flour, cornstarch, baking powder, and salt together into mixing bowl.
Beat eggs and sugar together in mixer bowl on medium-high speed until thick and doubled in volume.
Mix vanilla and melted butter in small bowl. Stir large spoonful of egg mixture into butter mixture, then gently fold back into egg mixture. Using rubber spatula, gently fold in flour mixture 1/4 cup at a time. Pour batter evenly over peaches.
Bake until cake is golden and center springs back when lightly pressed, 30-35 minutes. Immediately run table knife around edge of cake and invert onto serving plate. Serve.