• Preheat oven to 180°C (350°F) conventional (see note 1 if using a convection oven with a fan). Grease the sides of an 8x3-inch cake pan really well and line the bottom with parchment paper (see note 2).

Topping

• Core and thinly slice the peaches (there’s no need to peel them) and set aside (see video for best way to do this).
• In a small bowl, combine the brown sugar and melted butter. Pour the mixture into the prepared cake pan and spread it out evenly over the parchment.
• Arrange the peach slices on top in a spiral pattern, slightly overlapping each slice as you go. Set the pan aside.

Cake Batter

• In a bowl, sift together the flour, cornstarch, baking powder, baking soda, salt, and cinnamon. Whisk to combine and set aside.
• In a large bowl, beat butter, sugar, and oil with a hand or stand mixer for 2 minutes until light and fluffy.
• Add egg and mix on low speed until well combined.
• Mix in the milk, Greek yogurt, and vanilla on low speed until combined. Remove any batter from the mixer attachments, as the rest of the mixing will be done by hand.
• Add the dry ingredients to the wet ingredients and gently fold with a spatula until just combined. Do not overmix.
• Pour the batter over the peach layer in the cake pan and spread it out evenly. Tap the pan lightly on the counter once to remove any large air bubbles.
• Bake uncovered for 30 minutes, then loosely cover the top with foil and bake for another 30 minutes, or until a skewer inserted into the center comes out clean or with a few moist crumbs.
• Let the cake cool in the pan for 20 minutes, then run a thin knife around the edges to loosen it. Place your serving plate upside down on top of the cake pan and carefully flip the cake over.
• Give the cake pan a few taps, then lift it off to reveal the caramelized peach layer on top. If any peach slices stick to the parchment, simply place them back where they belong — no one will ever know! 🙂
• Allow the cake to cool to room temperature before slicing and serving.