Hot Cream Sponge Cake
 

• Baker Note; “When preheating the oven for my cakes, always use the ‘top and bottom heat’ setting. Please avoid using the fan-forced option, unless otherwise specified.
   
• Twenty minutes or longer before baking, set an oven rack in the lower third of the oven and preheat the oven to 165C°/ 325F°.
   
• For this recipe, I use a 20 cm ( 8-inch) x 12 cm (5 inches) high cake /pastry ring without a bottom. The bottom side of the cake ring has to be covered with a piece of parchment paper or aluminum foil; fold it tightly around the ring so that the cake batter does not come out of the sides. Make sure to place the cake ring on a baking sheet. Do not grease the sides. You can also use one 23 cm (9 inches) springform; Line the bottom with parchment paper, but do not grease the sides.
   
• Grease your wire racks with butter and set them aside; this step will prevent the cake from sticking to the wire rack.
   
• In a medium bowl, combine 175-gram all-purpose flour or pastry flour and 1 teaspoon of baking powder, sift twice, and set aside.
   
• Bakers Note; The ratio of egg white to yolk in an egg can vary to such a degree that you may need as few as seven or as many 8 for this recipe.
  Therefore, it is advisable to weigh the separate yolks and egg whites as mentioned in the recipe and add or reduce them if needed.
   
• Separate the egg whites from the yolks; Cover the yolks loosely with parchment paper and set the yolks aside for later. 
   
• Wipe your mixer bowl and whisk with a paper towel dampened with a little lemon juice to eliminate any trace of grease. 
   
• Put 210 grams of egg white and a pinch of cream of tartar in a spotlessly grease-free clean mixer bowl and whip on medium-high speed until medium peaks, about 3 minutes.
   
• Then slowly add the 250-gram superfine sugar, one tablespoon at a time, and wait for about 15 seconds before the next addition. Not rushing this process is key to making the perfect stable whipped meringue. This step takes about 3 minutes.
   
• When all of the sugar is added, mix on medium-high speed and mix until the meringue is shiny and stiff, about 3 minutes more.
   
• Stop the mixer and add all of the 140 grams of egg yolks on top of the whipped meringue, and mix on medium-low speed for just 1 second for each yolk. ( when you stop the mixer, you should still see many yolks traces). Try to keep most of the whipped meringue volume. Remove the bowl from the mixer.
   
• Sift the flour mixture onto the egg mixture in three increments. Use a balloon whisk instead of a spatula for maximum volume and gently fold the flour mixture into the batter until fully incorporated. Try to keep most of the volume. Periodically shake out the batter that collects inside your whisk, and work quickly so the whipped meringue doesn’t deflate. Add 1 teaspoon of vanilla bean paste and set aside while you melt the butter and cream.
   
• In a small saucepan, melt 20 grams of unsalted butter ( or heavy cream) and 55-gram heavy cream. Pour the warm butter and cream mixture ( or just the cream mixture) around the edge of the mixer bowl. Use your balloon whisk or a large silicone spatula and gently fold it very gently into the cake batter. Use your spatula at the end of the folding to reach the bottom of the bowl.
   
• You should have about 850 grams of cake batter; pour the cake batter into the prepared pastry ring or 23 cm (9 inches) springform.
   
• Bake in the lowest rack of the oven at 165C% 325F° until the cake is golden brown and spring back when gently touched with your fingertip and a toothpick inserted into the center of each cake comes out clean-about 40 to 45 minutes.
   
• If you have used a 23 cm (ginch) springform, the baking time is 30 to 35 minutes.
   
• Avoid opening the oven door before the minimum baking time has elapsed because this fragile cake could fall.
   
• As soon as it is baked, turn the cake upside down, still in the ring or springform, and cool until no trace of warmth remains about 90 minutes. Carefully remove the cake ring, and use a sharp knife to go around the sides to get the cake out of the cake ring.
   
• If not used right away, wrap the cake in plastic wrap.
   
• Place the cooled cake on your worktable or a turntable; gently rest your hand on top of the cake and, using a long serrated knife, begging to cut the cake into three equal layers. Each layer should be about 2,5 cm (1 inch)

Lemon syrup

• In a small saucepan over low heat, heat 75 gram of freshly squeezed lemon juice and 50 gram white sugar until the sugar is dissolved. It takes about 3 to 5 minutes. For lemon syrup that you need to soak in the cake, it is important to keep it runny.
   
• Remove from heat and set aside for now.

Lemon Poppy Seed & Greek Yogurt Frosting 
 

• Bakers Note: Use only heavy cream (or heavy whipping cream) with a 40% fat content. This higher fat content is key for whipping up a cream that's both thick and stable, providing the perfect base for your frosting. Ensure the cream is very cold for optimal whipping; placing the cream in the freezer for about 15 minutes before use can enhance the whipping process.
   
• Opt for a full-fat, natural Greek-style yogurt with a 10% fat content. The thick consistency of Greek yogurt, achieved by straining out the whey, makes it an ideal choice for creating a rich and creamy Whipped Yogurt Frosting. Avoid low-fat or fat-free yogurts, as their higher water content can result in a frosting that's too runny for your liking. Your Greek Yogurt should be notably thick. If you find the yogurt too watery, a simple fix involves straining it through a fine-mesh sieve over a bowl, covered with plastic wrap, and left to drain in the fridge for a few hours or, ideally, overnight. This step is crucial to ensure your Passion Fruit Yogurt Frosting achieves the perfect consistency, avoiding a watery outcome that could compromise your frosting's structure.
   
• If possible, use organic lemons; if you use regular lemons, make sure to scrub them thoroughly to remove pesticides and wax before using.  Use a Microplane to collect the lemon zest from about two lemons and set it aside for now. Then squeeze lemon juice from it. Place the lemon juice in the fridge to keep it cold.
   
• To make the frosting: In the bowl of your stand mixer fitted with the whisk attachment, add 150 grams of sifted powdered sugar, 600 grams of cold Greek yogurt (10% fat), two teaspoons of vanilla bean paste, (a large pinch of citric acid, if not using fresh lemon juice), and 600 grams of cold heavy whipping cream (40% fat)
   
• Whip the mixture at low speed for one minute, then turn the mixer to medium-high speed until the Greek Yogurt frosting is thick, fluffy, and stable, about  2 to 3 minutes. Whipped yogurt frosting destabilizes (softens) when overmixed, so keep an eye on the frosting as soon as it thickens.
   
• As soon as the Greek Yogurt Frosting is thick, if using freshly squeezed lemon juice, turn your mixer to low speed and slowly drizzle in the freshly pressed cold lemon juice; mix for 15 to 20 seconds more on medium speed.
   
• Remove the bowl from the mixer, and add two tablespoons of lemon zest and one tablespoon poppy seed. Combine with a spatula and have a taste, it is so delious.
   
• For maximum freshness and deliciousness, use it immediately or store in an airtight container in the fridge until needed. Re-whip if needed.

To assemble 
 

• Drain the two cans of mandarin slices.  Make sure they are dry before putting them in the cake.
   
• Be sure that the cake layers are completely cool before filling the cake; heat from a warm cake will melt the Yogurt frosting.
   
• Place the first cake layer on a baking sheet covered with parchment paper or a silicone mat; make sure that the baking sheet fits in your refrigerator. Add a few tablespoons of lemon syrup on top.
   
•  Spread one-third of the poppy seed frosting on top of the first cake layer and carefully smooth it out with the back of a spoon or an offset spatula.
   
• Divide 1/2 of the mandarin on top, add a few spoonfuls of frosting on top, and place the next cake layer on top; press down lightly to help it stick to the frosting, and repeat this step one more time.
   
• Place the final cake layer on top so that the bottom is facing up, providing a flat top for your cake. Press down lightly to help it stick to the frosting.
   
• Use an adjustable cake ring if you have one ( an adjustable cake ring is similar to a cake pan but without a bottom) around the cake. Cover the cake with plastic wrap and chill the cake in the refrigerator overnight or for at least 4 hours. This cake only gets better after a night in the fridge. It helps absorb the flavor and moisture from the frosting and makes the cake super soft and tender.
   
• If you don’t have an adjustable cake ring. Carefully pack the entire cake with plastic wrap and chill in the refrigerator overnight.
   
• Just before serving, take the cold Lemon Poppy Seed & Greek Yogurt Frosting out of the fridge. Re-whip if needed.
   
• Remove the cold cake from the fridge, and remove the plastic wrap and adjustable cake ring.
   
• Apply all of the Lemon Poppy Seed & Greek Yogurt Frosting all the way around the cake, from top to bottom, using an offset spatula. This frosting is enough to get a thin layer, as seen in my photos.
   
• Serve right away. Leftovers can be stored in the refrigerator for up to 24 hours.