Combine the first 4 ingredients in a bowl. Spoon into a 9-inch round cake pan coated with cooking spray.
Place 2/3 cup sugar and next 4 ingredients (2/3 cup sugar through egg) in a large bowl; beat with a mixer at medium speed until well blended (for about 5 minutes). Lightly spoon flour into dry measuring cups; level with a knife. Combine flour, baking powder, baking soda, and salt, stirring well with a whisk. Add the flour mixture to sugar mixture alternately with buttermilk, beginning and ending with flour mixture; mix after each addition.
Spoon batter over peach mixture in pan. Bake at 350° for 45 minutes or until a wooden pick inserted in center comes out clean. Cool for 10 minutes in pan on a wire rack. Place a plate upside down on top of cake, and invert onto plate. Serve warm with frozen yogurt and the caramel syrup.
Liked it a lot, without the caramel or frozen yogurt. Will probably use a bit more cornstarch next time, since the peaches were more gooey than I'd have preferred. It did, take longer to bake than indicated, too.
A great moist cake, but I mistakenly used white peaches not yellow, so the fresh peach taste wasn't quite what I hoped. Glad I used firm peaches though, or this seems like it would have stuck to the pan. Great pop of caramel to each bite, and a nice "peaches and cream" effect from serving with the ice cream.
I made this twice and learned that if the peaches are too ripe, the cake will not cook thoroughly or still seem overly moist when done. The second time, I used more firm peaches and the cake was better. I still have issues with the peaches sticking to the pan even with a springform, but it still looks and tastes great.
Quite delicious. I have never made an upside-down cake before and thus have no frame of reference. However, this was simple, smelled great when baking, and was delicious with some ice cream. I didn't use any caramel, not having any on hand, but would suggest that next time. Also I used brown sugar and nutmeg for the peaches as suggested and will continue doing so.
Made to recipe with two minor tweaks: used brown sugar for the peaches & dusted the very smallest amount of nutmeg on the fruit before topping with batter. Pretty inexpensive at this time of year if you can source ready-to-cook seconds from an orchard or fruit stand.