Cake with berries and cream

This is one of the most loved cakes in Sweden. It has so much potential to make your own style on it. Use any fruit or berries you want on top! The traditional ones have strawberries or mixed berries on top.
Components
Sponge cake
Vanilla custard
Strawberry jam
Strawberry syrup
Whipping cream
Fresh strawberries
Fresh blueberries

Ingredients 4 servings

Sponge cake
250 g (8.82 oz) eggs
130 g (4.59 oz) sugar
130 g (4.59 oz) wheat flour
30 g (1.06 oz) unsalted butter

Vanilla custard
240 g (8.47 oz) milk
60 g (2.12 oz) sugar
1/2 vanilla pod
19 g (0.67 oz) cornstarch
50 g (1.76 oz) egg yolks
11 g (0.39 oz) unsalted butter

Strawberry jam
66 g (2.33 oz) strawberries
134 g (4.73 oz) sugar

Strawberry syrup
50 g (1.76 oz) strawberries
20 g (0.71 oz) water
50 g (1.76 oz) sugar

Instructions

Sponge cake
Preheat oven to 180° C (356 degrees Fahrenheit) and grease 4 small round cake tins with soft butter.
Melt the butter and set it aside to cool.
Whip the eggs and sugar on high speed until the mixture has tripled in volume.
Sift the flour and fold it carefully into the egg mixture until just incorporated.
Fold in the butter.
Pour the batter into the cake tins and bake for 20 minutes or until the cakes feel spongy upon light pressure.
Cool the cakes completely before assembly.

Vanilla custard
Mix all the ingredients for the vanilla custard in a small pan and then bring to a boil over medium/high heat. Let it boil for 1 minute.
Strain the mixture though a sieve and set aside to cool. Cover the surface with plastic wrap to prevent a skin from forming on the custard.

Strawberry jam
Put all the ingredients for the strawberry jam into a small pan and bring to a boil while pressing the strawberries with a fork.
Boil the jam for 5 minutes while stirring and then set aside to cool.

Strawberry syrup
Put all the ingredients for the strawberry syrup into a small pan and bring to a boul whithout pressing the strawberries.
Boil the syrup for 5 minutes and set aside to cool.

Assembly
Whip the cream to soft peaks.
Cut the fresh berries in halves.
Cut the sponge cakes in 3 pieces each.
Spread the vanilla custard on the bottom layer and strawberry jam on the mid layer.
Dip a pastry brush into the strawberry syrup and brush the top layer.
Pipe the cream around the edges of the cake and smooth with spatula. Pipe cream rosettes on top of the cake, around the edge.
Put on the fresh berries. Gently brush the fresh berries with the syrup to give them some gloss.
Arrange blueberries around the cake.