Combine the room temperature butter with the two sugars in a bowl. Then mix in the egg.
Sieve flour, black cocoa powder, cocoa powder, salt, bicarbonate soda, baking powder into the butter mixture until just combined.
Add chopped white chocolate and mix through. Chill dough for one hour.
Get a 24 capacity mini cupcake tray. Wigh out 25g balls of dough and place in the tray. Press the dough towards the sides to create a cavity to form the cookie cup.
Bake for 14 minutes on 180℃. Allow to cool for 2 minutes before pressing the cookie dough back into shape with the handle of a wooden spoon.
Chocolate Filling
Melt the dark chocolate in the microwave and roll the chocolate on the inside of the cookie cups.
Chocolate Marshmallow Filling
In a stand mixer bowl add the 50ml water and then sprinkle powdered gelatine over to allow it to bloom.
In a medium saucepan add the caster sugar and water and the clear vanilla. Place candy thermometer on the side of the saucepan. On medium low heat sugar until it reaches 118℃ to 120℃.
Pour the sugar syrup into the gelatine bowl and whisk on medium until the marshmallow reaches stiff peaks. This can take 10 minutes or more. Add the tbsp of cocoa powder and mix to combine.
Place into a piping bag fitted with a large star tip and pipe onto the cookie cups.
Notes
Note: Keep in an air tight container at room temperature.Note: Eat within 3 days.