Preheat oven to 350 degrees.
Spray a 9-inch round cake pan with nonstick cooking spray; set aside.
3 cups thinly sliced peeled peaches
1 tbsp sugar
1 tsp cornstarch
1 tsp lemon juice
Combine the peaches, sugar, cornstarch, and lemon juice in a mixing bowl. Spoon mixture into the prepared cake pan; set aside.
2/3 cup sugar
1/4 cup butter, softened
2 tsp grated lemon peel
1 tsp vanilla extract
1 large egg
Place the above 5 ingredients in a large mixer bowl; beat at medium speed until well blended, about 5 minutes.
1 1/4 cups all-purpose flour
1 tsp baking powder
1/2 tsp baking soda
1/8 tsp salt
3/4 cup buttermilk
2 1/4 cups vanilla frozen yogurt
6 tbsp caramel sundae syrup, warmed
Combine the flour, baking powder, baking soda, and salt; stir well with a whisk to blend well. Gradually add the flour mixture to the sugar mixture alternately with the buttermilk, beginning and ending with the flour mixture. Mix after each addition.
Spoon the batter over the peaches in the cake pan.
Bake at 350 degrees for 45 minutes or until a wooden toothpick inserted in the center comes out clean. Cool in the pan on a wire rack for 10 minutes. Place a plate upside down over top of cake; invert pan to place cake on plate.
Best served warm with the frozen yogurt on the side and the warm caramel syrup over the cake and yogurt.