Start this recipe by making 2 recipes of the pastry cream. Beat together the eggs and sugar in a bowl with a whisk until pale. Heat the milk and seeds from the vanilla pod in a saucepan and bring almost to the boil. Pour half of this mixture gradually over the egg mixture whisking constantly, then pout in the remaining. Transfer back into the saucepan and bring to the boil. Take off the heat, stir in the chocolate till melted. Stir in the butter and pour into a bowl and cover with cling film. Allow to set in the fridge. When ready, place a layer of lady fingers into a large trifle bowl and sprinkle over some of the coffee liqueur. Spread over half of the chocolate pastry cream. Cover with half of the chocolate cake cubes and soak with a little more liqueur. Follow with half of the strawberries and then half of the chopped chocolate. Repeat this process with the remaining half ingredients. Place into the fridge to set for at least 2 hours before serving.