Please use all the measurements in metric system and use a scale.

Chocolate sponge cake steps can be found at my other recipe. The only different is that mixing all-purpose flour and cocoa powder well before mixing with the cake batter. Bake in a 8" round cake pan

Fool proof sponge cake - https://allthecooks.com/@polarbeer/foolproof-sponge-cake-5yctVvyrLY

Let the cake cool completely on a cooling rack. Need a 8-9" springform pan (has to be springform = removable bottom). Cut out 11-12" parchment paper, lay it over the bottom piece and attach the wall of the pan. With parchment paper on the bottom, it'll be easier to remove the cake out of the pan bottom later. Place the chocolate cake inside the pan, if the cake is halfway higher than the pan height, then trim off the cake until it's about 1/3 of the pan height.

Custard pudding: Mix gelatin in 2 tbsp water, let aside. Heat milk and heavy cream in a sauce pan on medium heat until simmering. Beat egg yolks and sugar until it turns pale yellow and look fluffy, then add corn starch, mix well. Slowly pour in the warm milk mixture into the egg mixture while stirring constantly to prevent cooking the egg. Pour the mixture back into the sauce pan, stir constantly on medium heat until the mixture starts to turn thicker. The mixture will not be as thick as a normal custard (because we'll add gelatin later). Turn off the heat, add the gelatin, mix well until combined. Add the vanilla extract and mix well. Wait until the mixture cools down (mix occasionally) then pour over the cake. Store the pan in the fridge for 2 hours, or in the freezer so the pudding layer sets faster.

Yogurt mousse: Mix gelatin in 2 tbsp water, wait about 5 minutes for the gelatin to soak all the water. Microwave for 20 seconds. Mix the melted gelatin into the yogurt. In another bowl, add sugar into heavy cream, beat until soft peak (when you lift up the whisk, the cream forms a peak, but still not too firm). Carefully fold the yogurt into the whipped heavy cream until combined. Pour the mixture over the custard pudding. Because the whipped heavy cream is cold, the gelatin in the mixture will make the mixture firm up fast. If the yogurt mousse starts to firm up, try to make the top later even with a spatula. Let cool in the fridge.

Mix gelatin in 2 tbsp water, wait about 5 minutes for the gelatin to soak all the water. Cut strawberries in small pieces or use a food processor. And water to the strawberry puree, let it simmer in a sauce pan for about 10 minutes, add sugar to taste, I would just add about 1 tbsp sugar. Strain the mixture, toss of thick strawberry paste. Add the gelatin into the hot strawberry sauce, stir well. Wait until the mixture cools down, mix occasionally, then pour over the yogurt mousse. Let cool in the fridge completely for about 4 hours.