Step 1: Make the Chocolate Custard

1. Heat 500ml of ready-made custard in a saucepan over low heat.
2. Add 150g of chopped dark chocolate and stir until melted and smooth.
3. Transfer to a bowl and let cool completely.

Step 2: Whip the Cream

1. Add 600ml double cream and 2 tbsp icing sugar to a large bowl.
2. Whip until soft peaks form. Cover and refrigerate.

Step 3: Prepare the Swiss Roll

1. Slice the jumbo swiss roll into 1–2cm thick slices.
2. If using, drizzle 4–5 tbsp of kirsch over the slices and let them soak for 5 minutes.

Step 4: Assemble the Trifle

1. First Layer: Arrange swiss roll slices along the base and sides of a trifle bowl.
2. Second Layer: Pour half the chocolate custard over the swiss roll slices.
3. Third Layer: Add half of the cherries (in syrup or kirsch) and half of the brownie bites.
4. Fourth Layer: Spread half the whipped cream evenly.
5. Fifth Layer: Add a thin layer of cherry jam or conserve.
6. Repeat the layers, finishing with a thick layer of whipped cream.

Step 5: Garnish and Chill

1. Decorate with fresh cherries and grated chocolate on top.
2. Chill in the refrigerator for at least 1 hour before serving.