Sponge cake with chocolate glazing and apple custard

Ingredients:

• for the pastry: 4 eggs, 8 tbsp granulated sugar, 3 tbsp lukewarm water, 1 sachet baking powder, 8 tbsp flour 
• to line the tray: 20g butter, approx. 2 tbsp flour
• for the apple custard: 1.5kg apples, 900ml water, 8 tbsp granulated sugar, 2 packs (2x40g) ready-to-cook vanilla pudding powder
• for the chocolate glazing: 200g dark chocolate, 150g icing sugar, 60g butter or block margarine, 6 tbsp water

1. Separate the eggs. Beat the yolks for 2-3 minutes to form a thick cream with half of the sugar and the water. Whip the egg whites into a thick foam, adding the rest of the sugar. Mix the baking powder and the flour. Put a third of the whipped egg on the yolk-sugar mix. Sift a third of the flour-baking powder mix on top of this and fold in gently. Add the remaining foam and flour in the same manner, in two parts. 

2. Spread it in a greased and flour-powdered large baking tray and bake for about 10 minutes in a pre-heated oven at moderate heat (180 °C; or 165 °C in a fan-assisted oven). 

3. Peel the apples and remove the core, cut them into 1cm pieces. Boil 800ml water and add the sugar. Add a third of the apples and cook them until tender in 2-3 minutes, then lift them out with a sieve and let them cool. Proceed in the same manner with the rest of the apples, in two batches. Mix the vanilla pudding powder with 100ml water until smooth and add it to the apple cooking water; stir and cook into a thick custard in a few minutes. Add the apple dices and spread it on the sponge cake. Let it congeal in the fridge. 

4. Melt the components of the glazing, stirring them in a smaller pot. Spread it evenly on the apple custard. Leave to congeal. Cut into squares with a knife dipped in hot water and serve with quince jam.