Prep: Heat oven to 360°F (180°C). Line a 9x13 inch (22x33cm) cake pan with baking parchment.
Cake:
Egg whites:Separate eggs. Set yolks aside in large mixing bowl. Beat egg whites to stiff peaks in separate mixing bowl.
Egg yolks:Add sugar and vanilla extract to egg yolks and beat until light and fluffy.
Add dry ingredients:Combine flour, cornstarch, baking powder and salt; slowly add to yolk mixture while beating on low speed.
Finish batter and bake:Gently fold in egg whites until cake batter looks smooth. Carefully spread batter in prepared pan and bake around 20 minutes, until lightly golden.
Cool:Spread strawberry jam over hot cake, then cool in the pan on a wire rack until at room temperature.
Cream layer:
Beat cream cheese in a large mixing bowl until cream. Add heavy whipping cream, icing sugar and vanilla and beat on high speed for 3-4 minutes, until cream is light and fluffy. Carefully spread cream filling over cooled cake. Chill in the fridge for 30 minutes.
Finish:
Arrange cut strawberries over cream layer. Prepare jello according to package directions, allow to cool a bit (it should still be runny, but it shouldn't be blazing hot - otherwise it will melt the cream layer). Evenly pour over strawberries, then chill until set. Slice to serve.
Video
Notes
Baking tips
Eggs: The cake gets most of its rise from the beaten eggs. In order to have the greatest success, follow these tips:
Make sure to beat the egg whites really well; you should be able to slowly invert the bowl without them falling out (do this test VERY carefully, or you could end up with a huge mess!)
Also, beat the egg yolks with the sugar and vanilla very well. Beat long enough until the mix turns light in color and increases in volume.
Be very gentle when folding in the egg whites - you don't want to knock out all of the air! As a little trick, I fold in ⅓ of the egg whites first with a little more strength to slack down the batter, then very gently fold in the rest.
While being very careful, make sure to fold the egg whites in completely. You don't want large flecks of egg white left in the batter - otherwise your cake will rise very unevenly.
Baking: Don't worry if the cake puffs up a lot in the oven, it will sink back down once you take it out!Cream filling: Make sure to whip the cream long enough, until it's notably fluffy. Otherwise you'll have a brick of cream cheese on your cake.Chilling: Definitely chill the cake long enough before slicing! Otherwise it won't be neat.
Ingredient notes
Cake: There are no ingredient substitutions I can recommend for the cake part of this recipe. Please make it as-written. Yellow sponge cakes are simple to make, BUT they are not very forgiving if you don't follow the recipe exactly.Cream: Please use cream labelled as "heavy whipping cream" and chill it well before using. Otherwise the cream will not work.Jello: You can use a different glaze meant for cakes, but please make sure it's one that sets. Otherwise the cake will be a big mess, and that's really a shame.Strawberries: Feel free to use a mix of berries, or other berries. Use blueberries, blackberries and raspberries whole on the cake - if you cut them, their juices will run out and stain the cake.
Storage
The cake keeps well covered in the fridge for up to 2 days. I do not recommend freezing, because the texture of the cake layer and the fresh strawberries really do not hold up too well in the freezer.