For the cake topping, add the flour, sugar, baking powder, salt, and baking soda to a large bowl and whisk to combine. (Or add everything to a gallon-sized zip-top plastic bag and shake it up.)
For the peach layer, add all ingredients to a 9 by 13-inch baking dish, and stir to combine.
Sprinkle the cake topping evenly across the peaches. Don’t stir! We want the peach layer and topping layer separate.
Arrange the butter slices evenly across the top.
Bake until the cake is golden on top and the filling is bubbling around the outside, about 40 to 45 minutes.
Serve hot, cold, or at room temperature.
Notes
Peaches: If peaches aren't in season, you can use frozen peaches instead of fresh. Thaw them to room temperature first, and drain off all but 3 tablespoons of the liquid.
Nuts: If you want to add nuts, sprinkle on about 1/2 cup of chopped pecans (or whatever your favorite nut is) before sprinkling on the flour mixture. With peaches, pecans, and bourbon you'll have a cake with all the flavors of Georgia!
Serving Suggestion: This gooey, decadent fruity cake is delicious on its own. However, you can take it to the next level by serving it warm with a scoop of vanilla ice cream or a dollop of fresh whipped cream. Or go with a drizzle of butterscotch sauce!