• Halve and pit the peaches, but leave their skins on. Cut each half into 3 wedges.  If using frozen sliced peaches, do not defrost. Set aside
• Preheat your oven to 350°F. Butter a 9-inch cake pan, line bottom with parchment paper and brush the paper with butter. Set aside

Prepare the Caramel

• In a medium saucepan, combine the brown sugar and butter over medium-low heat, stirring until the sugar dissolves. Continue to cook, without stirring, until the mixture turns an amber caramel color, about 3-4 minutes. Be careful the sugar doesn’t burn. If it starts to smoke, remove it from the heat. Turn off the heat and pour in the heavy cream, being careful as it may splatter. Stir well. Pour the caramel into the prepared cake pan and set aside to cool for a few minutes
• Arrange the peach wedges in concentric circles in the pan, on top of the caramel, placing them close together, as they’ll shrink once baked. Set aside while you make the cake batter

Prepare the Cake

• In a medium bowl, whisk together the flours, baking powder and salt. Set aside
• In the bowl of a stand mixer with the paddle attachment, mix together the butter and sugars on medium speed until light in color and fluffy, about 5 minutes. Add the eggs and vanilla and mix until smooth, about 1 minute more. With the mixer off, scrape the bottom and sides of the bowl with a spatula
• With the mixer on low speed, add in ⅓ of the flour mixture and mix until incorporated, about 15-30 seconds. Combine the milk and oil and add half to the batter, mixing until smooth, about 30 seconds. Add another ⅓ of the flour mixture, mixing again for about 15-30 seconds, followed by the remaining milk/oil. Add the remaining flour and mix until completely smooth, about 30 seconds more, stopping to scrape the sides and bottom of bowl at least once to ensure all of the batter is evenly incorporated
• Pour the cake batter over top the fruit and caramel, making sure it is evenly distributed. Smooth with a spatula
• Place the cake pan on a baking sheet to catch any spillover, as the fruit and caramel tend to bubble up while baking. Bake for 40-45 minutes or until a toothpick inserted in the center comes out clean
• Remove the cake from the baking sheet and place it on a cooling rack. Let the cake cool for just a minute, until the fruit stops bubbling. Place a cake plate (or cutting board) over the cake and, using oven mitts, carefully flip the cake over. Gently remove the cake pan and parchment, if it’s stuck to the cake.
• Using a fork, rearrange any peaches that may be out of place or have fallen off the sides. Let the cake cool until still warm but not hot. Serve warm with whipped cream