250g packet Arnott’s Salada Original biscuits
200g dark cooking chocolate, broken into pieces
2 tsps vegetable oil
1¾ cups sweetened condensed milk
1½ cups brown sugar, firmly packed
125g unsalted butter, chopped
¼ cup milk
Grease a 19cm x 30cm lamington pan. Line the base and sides with baking paper, extending paper 3cm above the pan edges.
To make the caramel, place condensed milk, sugar and butter in a large saucepan over a medium heat. Stir until the butter is melted. Bring to a boil. Boil, stirring constantly for about 10 minutes, or until golden brown and slightly thickened.
Remove pan from heat. Stir in milk until well combined. Stand for 5 minutes.
Arrange one-third of the biscuits, in a single layer, over base of prepared pan. Pour over 1 cup of the caramel. Spread evenly. Top with another layer of biscuits. Repeat layering with remaining caramel and biscuits, finishing with a caramel layer. Stand at room temperature for 20 minutes.
Combine the chocolate and oil in a medium heatproof bowl. Sit bowl over a saucepan of simmering water. Stir until melted and smooth. Remove from heat. Pour over slice. Spread evenly. Refrigerate for about 6 hours, or overnight until firm.
Remove slice from fridge 30 minutes before serving. Lift out of pan onto a chopping board. Cut into squares.