Preparation

• Preheat the oven to 350°F with a rack in the center. Line the bottom of an 8" round pan with a parchment round and lightly grease the bottom. Leave the sides of the pan ungreased.
• Bring a pot of water to a boil and score the bottoms of your peaches with an “X” shape about ½" big. Boil the peaches for 30 seconds, then transfer them to an ice bath. Remove the skin using a paring knife or your fingers. Slice the peaches in half, remove the pits, then cut each half into thirds. You should have about 2 cups peach slices (300g). Set aside.
• In a wide, heavy-bottomed pot or pan, distribute the sugar and salt evenly. Cook over medium heat until large swaths begin to melt. Once the sugar has melted and reached deep amber color, immediately transfer the caramel to the prepared pan and tilt to spread to the edges. Set aside to cool slightly and lay the peach slices over the cooled caramel.
• In the bowl of a stand mixer fitted with the whisk attachment, combine the eggs, sugar, and salt. Whip on high speed until pale, foamy, and tripled in volume for about 8 to 10 minutes. The batter should sit on the surface briefly when raised with a whisk.
• Remove the bowl from the mixer and whisk in the vanilla. Sift the flour evenly over the eggs, then gently fold into the egg mixture. Transfer the batter to the pan with the peaches.
• Bake the cake for 35 to 40 minutes, until the surface is golden brown and springs back when lightly pressed, and a toothpick comes out clean.
• Transfer the cake to a wire rack and let it cool for 10 minutes. Run a small offset spatula or knife around the circumference of the pan to loosen edges, then invert onto a serving plate and let cool for an additional 20 minutes.
• To make the whipped cream: Whip heavy cream, salt, and confectioners' sugar until it holds soft peaks. Serve with the cake or store in the refrigerator up to 2 hours.
• Store any leftover cake airtight in the refrigerator for up to 1 week. Warm in a 350°F oven for 10 minutes before serving.