Prepare boxed mix brownie with eggs and oil and bake according to packet instructions. You can do this the day before to save time.

Once cool cut the brownies into 1 inch squares and set aside in 3 equal piles.

Add frozen raspberries and caster sugar to a glass jug, microwave on high for 1 minute then stir. Microwave for another minute then stir again. Set aside to cool until ready to assemble.

Place half of the sliced strawberries in the bottom of a trifle dish or large serving bowl.

Pour over a third of the raspberry sauce. Add the first layer of brownie pieces. Carefully spoon over half of the whipped cream.

Next add a layer of custard and smooth it to the edges with a spoon. Add another third of raspberry sauce and the second layer of brownies.

Place the rest of the strawberries on top and the rest of the custard, smooth to the edges.

Now add the third layer of brownies and the last of the raspberry sauce. Top with the rest of the whipped cream and spread until the top is smooth.

Decorate with crumbled Flake, fresh raspberries and a sprinkle of icing sugar.

Refrigerate for at least 3 hours before serving or preferably overnight.