Directions

• Prep Work
• Peel and core the apple, then slice it into 1cm thick wedges. Place them in a microwave-safe bowl, cover with plastic wrap, and microwave for 2.5 to 3 minutes until the slices are slightly softened and tender.
• Making the Caramel Base
• In a small saucepan, combine the granulated sugar and 15g of water. Place over medium heat.
• Let the sugar melt and bubble. Once it darkens to a deep amber color (similar to the caramel sauce used for custard puddings), remove it from the heat immediately.
  Quickly pour the hot caramel into the bottom of your cake tin.
• Tilt the tin to spread the caramel evenly across the entire base.
• Arrange the softened apple slices on top of the caramel. Place two slices in the very center, and arrange the rest in a beautiful radial (starburst) pattern overlapping slightly, hiding the curved edges.
• Making the Cake Batter
• Melt the unsalted butter in the microwave and keep it warm (around 40°C / 104°F).
• Whisk the whole eggs in a bowl to break them up, then add the brown sugar. Place the bowl over a double boiler (bain-marie) with hot water. Warm the mixture while stirring continuously with a hand mixer until it feels warm to the touch (around 40°C / 104°F).
• Remove the bowl from the water bath and whip the egg mixture on high speed with the hand mixer.
• Continue whipping until the batter becomes thick, pale, and mousse-like, holding its volume. When you lift the beaters, it should leave a distinct ribbon trail that stays on the surface for a few seconds.
• Sift the almond flour, cake flour, baking powder, and cinnamon together directly into the whipped egg mixture.
• Gently fold the ingredients together using a rubber spatula just until the flour disappears and no dry pockets remain.
• Pour in the warm melted butter and gently fold with the spatula again.
• Mix until the butter is completely incorporated and the batter is smooth and uniform.
• Baking & Finishing
• Pour the batter into the prepared cake tin over the apples and caramel.
• Bake in a preheated oven at 180°C (350°F) for 25 to 30 minutes. (Tip: As the caramel sauce can bubble up and leak during baking, it’s a good idea to wrap the bottom of your cake tin in aluminum foil before putting it in the oven).
• Once baked, let it cool slightly. Run a sharp knife around the edges of the tin to loosen the cake, then carefully invert it onto a serving plate. Gently remove the bottom base of the tin using a knife if it sticks.
• Warm a small amount of apricot jam in the microwave until liquid, and gently brush it over the top of the warm apples for a beautiful, glossy finish.
• Place the cake in an airtight container and store it in the refrigerator for at least one full day. It reaches its peak flavor and perfect moistness on days 2 and 3!
• Baking Notes for Your Readers:
• Resist the temptation to eat this straight out of the oven! Letting the cake rest for 24 hours allows the caramel and apple juices to fully hydrate the sponge, turning it into a melt-in-your-mouth delicacy.