For the Sponge Cake

Cup of Yum
1. Preheat the oven to 350 F. Line the bottom of an 8-inch square baking pan with parchment paper.
2. In a medium bowl, whisk together cake flour, baking powder, and salt until combined.
3. In a large mixing bowl, whisk together egg yolks, ¼ cup of the sugar, oil, water, and vanilla extract until pale and frothy.
4. Sift half of the flour mixture over the yolk batter and stir well using a whisk. Sift the remaining half and beat the mixture well until it is smooth and lump-free.
5. Meanwhile, beat the egg whites and cream of tartar in the stand mixer. Once soft peaks form, gradually add the remaining ¼ cup of sugar while the mixer is still running until stiff peaks form.
6. Fold the beaten egg whites gradually into the yolk batter using a rubber spatula. The mixture should be uniform and color.
7. Pour the batter into the prepared pan. Tap the pan lightly against the counter to get rid of any air pockets.
8. Bake the cake at 350 F for 15-18 minutes or until the cake springs back to the touch.

For the Custard

1. In a large bowl, combine egg yolks, sugar, and cornstarch. Stir until smooth and well blended.
2.  In a saucepan over low heat, bring the milk to a simmer low heat until it begins to gently bubble along the edges of the pan.
3. Slowly ladle a small amount of the milk into the egg yolk mixture while whisking. Continue to add a small amount of milk at a time, whisking regularly.
4. Return the egg-milk mixture to the pan and cook over low heat, whisking regularly, until it simmers and thickens.
5. Turn off the heat and stir in the butter and vanilla extract.
6. Transfer to a bowl with a lid. Allow to slightly cool and press a plastic film wrap directly on the surface to prevent skin from forming on top. Refrigerate for 1 to 2 hours to cool and set.

For the Gelatin

1. In a large bowl, sprinkle the gelatin powder into the ¼ cup cold water to separate the granules. Let stand for 1 minute.
2. In a medium saucepan, combine fruit cocktail juice and sugar. Bring to a boil.
3. Turn off the heat and add the gelatin, stirring for about 1 to 2 minutes or until it is dissolved. Set aside to cool to slightly cool.

To Assemble

1. Transfer the cooled cake into a square glass dish of the same size. 
2. Spoon the cooled custard over the cake and spread evenly to coat. 
3. Arrange the fruit cocktail in an even layer over the custard.
4.  Pour the gelatin over the fruit cocktail. 
5. Allow it to set for about 30 minutes. Refrigerate for about 6 hours or overnight to firm and cool completely. Slice into serving sizes.