Combine all the ingredients in a bowl and refrigerate until needed.
Use a cookie cutter to cut circles the same size as the serving cups.
Split the rounds into two thinner circles.
Place the mascarpone layer into a piping bag.
Place the cooled chocolate custard into a piping bag.
Place the cooled raspberry coulis into a piping bag.
Pipe a layer of chocolate custard into the bottom of the cups.
Press a brownie circle into the cups.
Add a layer of raspberry coulis to the cups.
Add 4 dots of Chantilly mascarpone to the layers.
Top with another round of chocolate brownie.
Cover the chocolate brownie with more chocolate custard.
Put a generous squeeze of Chantilly mascarpone on top and add a fresh raspberry to the top.
Sprinkle chocolate flake over the Christmas Trifle for decoration.