For the shortcrust pastry
Place the eggs and yolks in a tall, narrow container, pour in the oil in a slow trickle and blend it all together with a hand blender. Tip the mixture into a food processor and add the flour and sugar, followed by the lemon zest and vanillin powder. Mix the ingredients until you have a smooth dough. Leave the dough to rest in the fridge for around one hour. Grease the moulds and line them with the dough, using around 30‒50g (1-1.7oz) per portion. Cook in a conventional oven at 180°C (356°F) for 10/12 minutes. Leave the pastry cases to cool before adding the cream.
PREPARATION OF THE FILLING
The coffee and meringue creams will be blended together. Read below to find out how to prepare each of them.
For the coffee cream
Start by making the coffee and chopping the chocolate. Beat the eggs, yolks and sugar together in a bowl, then add the cornstarch. Don't forget this basic rule: mix slowly by hand.
Heat some water in a large pan. Once it has come to the boil, pour the egg mixture into the water and cook for around 2 minutes. This will produce a thick mixture. Add the coffee you prepared earlier, remove from the heat and add the chopped chocolate, mixing well with a whisk or hand blender until the chocolate has melted completely. Leave the cream to cool in the fridge.
For the meringue cream
Place the ingredients in a bowl, and whip until the mixture is thick and foamy enough that it stays in place when the bowl is turned upside down. This phase can take up to 5 minutes. Once the mixture has cooled, add around 50g (1.7oz) of meringue cream for every 150g (5.2oz) of mixture and mix thoroughly.