Preheat oven to 190'C.
Line a baking tray with baking parchment.
Separate the eggs, putting the yolks into one large bowl and the whites into another. Add the demerara sugar to the yolks and whisk for about 5 minutes or until the mixture is pale and thick enough to leave a trail when the whisk blades are lifted. Sift the flour into the mixture and gently fold it together with a spatula.
Beat the egg whites until they are stiff and then fold them into the cake mixture one third at a time.
Pour the mixture into the lined baking tray and carefully spread to the edges using a pallet knife.
Bake for 10-12 minutes - the cake should feel firm to the touch.
Put a large sheet of baking parchment on the work surface and sprinkle lightly with caster sugar. Turn the cake out onto the parchment and peel off the lining paper. Cover with a clean tea towel and leave to cool completely.
Beat together the egg yolks and the sugar until pale and fluffy. Add the vanilla extract and the kirsch. Mix well and then sift in the flour, folding it in as you go.
Bring the milk to the boil and then add to the mixture, stirring all the time. Return the mixture to the pan and continue stirring over a medium heat until the mixture is thick and coats the back of a spoon. Remove from the heat and whisk in half of the butter. Allow to cool and then whisk in the remaining butter. The mixture should be thick, creamy and smooth.
Hull the strawberries and cut them in half.
Line your cake tin with baking parchment. Use the base of the cake tin to cut a circle of sponge cake the same size as the tin. Carefully place the cake into the cake tin. Arrange the strawberries around the edge of the cake tin with the cut size facing outwards. Pour the crème pâtissière into the tin and spread it out evenly, smoothing the top with a palette knife.
Dust your work surface with icing sugar and then roll the marzipan out to a thickness of 3mm. Carefully lift the marzipan and place it on top of the crème pâtissière. Smooth it down and then trim away the edges. Use a blowtorch to glaze the marzipan to a light golden colour. Decorate the top of the cake with any remaining strawberries. Chill the cake in the fridge for at least 30 minutes before removing from the tin.
«Prepare this dessert a few hours in advance to allow it to set.»