Finely ground chocolate cookies/biscuits in a food processor. I have used bourbon biscuits.
Pour biscuit crumbs into a bowl. Add melted butter and stir well.
Pour the mixture into cupcake moulds lined with liners. Press down and flatten it out. Place it in the refrigerator for 20 minutes to firm up. Preheat oven to 170-degree Celsius.
Bake the crust for 8-10 minutes. Take it out of the oven and place it on a wire rack to cool down completely.
To make the filling:
Add chopped dark chocolate in a bowl.
Pour heavy cream in a saucepan and bring it to a simmer over medium-low heat. Don’t boil it.
Remove from heat and pour it over the chopped chocolate. Let it sit for 1 minute.
Whisk gently until smooth. Add butter and mix well until melted.
Add egg and milk into the mixture. Whisk well.
Reduce oven temperature to 150-degree Celsius. Pour 2 tbsp mixture over biscuit crusts and bake for 15 minutes.
Take it out of the oven and allow it to cool down completely before serving.