For the poppy biscuit:
Sift the flour, and mix it with salt, poppy seeds and the baking powder. Heat up the butter and the milk. Whip the eggs with sugar for 15 minutes; add the dry ingredients, and mix gently with a spatula from the bottom to the top.
Then, add the warm milk and butter, and mix gently with a spatula. Repeat these actions thrice. Bake the biscuit in an 18 cm (7 inch) mold at 160C (320F) for 30-40 minutes.
The exact baking time depends on the oven.
For the strawberry soufflé:
Boil the strawberries and the sugar, and mash with a blender. Whisk the cream and the yoghurt until fluffy; add the strawberry puree and the melted gelatin. Pour into a 16 cm (6.3 inch) mold, and place it in the freezer for stabilization.
For the kiwi crème:
Pour the gelatin with water, and place it in the fridge for swelling.
Mix the kiwi puree, sugar, egg yolks and an egg in a small bowl. Stir the mixture well. Heat it over a low heat to 82C (180F), stirring it constantly with a whisk; the mixture should thicken a little.
Remove the mass from the heat, and add the swollen gelatin.
Stir it with a whisk until the gelatin dissolves completely.
Cool the mass to 35C (95F), and add the diced room temperatured butter; whip it with a blender until smooth. Pour the soufflé into two16 cm (6.3 inch) molds, and place it in the freezer until stabilized.
For the creamy custard:
Mix all the ingredients, and quickly whisk with a hand mixer until firm.
Assembling the cake:
Cut the biscuit into 4 cake layers. Assemble the cake, following the next order:
A soaked biscuit layer (you can use milk) – the custard – kiwi crème – the custard – the biscuit – the custard - the strawberry soufflé – the custard – the biscuit – the kiwi crème – the custard - the biscuit.