Begin by following the boxed brownie mix instructions. Mix the brownie mix with 2 eggs and the vegetable oil (or melted butter), then bake according to the packet instructions.

Once the brownies are cooled, cut them into 1-inch squares and divide them into three equal piles.

In a glass jug, combine the frozen raspberries and caster sugar. Microwave for 1 minute on high, then stir. Repeat this for another minute until the raspberries have broken down into a sauce. Allow the mixture to cool.

Start by placing half of the sliced strawberries at the bottom of a trifle dish or a large serving bowl.

Pour over a third of the raspberry sauce, then add the first layer of brownie pieces.

Carefully spoon half of the whipped cream over the brownies.

Add a layer of custard, ensuring to smooth it out to the edges, then drizzle on another third of the raspberry sauce and layer with the second pile of brownies.

Scatter the remaining strawberries on top, followed by the rest of the custard. Smooth this layer to the edges.

Add the third layer of brownies, followed by the last of the raspberry sauce. Top with the remaining whipped cream.

Crumble the Flake chocolate bars on top along with fresh raspberries and a sprinkle of icing sugar.

Cover and refrigerate for at least 3 hours, or preferably overnight.