In a food processor blitz up the custard creams and add in the butter. Mix again until well combined. Grease a 12
Cup muffin pan, then spoon in a heaped tablespoon of mix into each hole. Use the back of a teaspoon to level off each biscuit base.
Place the milk into a small pan and place on a medium heat. Cut the vanilla pod in half lengthways and add to the milk. Warm the milk up and let the vanilla infuse.
In a separate bowl beat together the egg with the egg yolks and caster sugar. Once the milk is warm but not boiling take off the heat and slowly beat through the egg and sugar mix. Once well combined, stir through the cornflour. Leave to cool.
Once cool, pour the custard mix into a measuring jug and divide evenly between your 12 biscuit bases that you made earlier.
Bake in a preheated oven at 180°C for 15 minutes until cooked through.