[Preparation]

1. Preheat oven to 160°C. Grease a 3cm-deep 30cm x 20cm lamington or slice tin. Line base and two long sides with baking paper, extending paper 5cm over the two long sides.

2. For the Biscuit Base: Cream softened butter and sugar until pale in colour. Fold in flour lightly until the mixture is crumbly. Transfer mixture to the prepared tin . Press down to evenly compact with the back of a spoon or the flat underside of a glass ; press with a piece of baking paper on top of mixture to prevent sticking to spoon or glass. Bake at 160°C for 30 minutes, or until light golden brown . Remove from oven and turn oven temperature up to 180°C.

3. For the Salted Caramel Filling: Combine sweetened condensed milk, golden syrup, butter and salt in a saucepan. Stir over medium-low heat for about 15 minutes, or until the caramel mixture is golden brown; pour over the biscuit base . Spread evenly to level the surface. Return to oven and bake at 180°C for 10 minutes remove from oven and let cool until the surface set.

4. For the Chocolate Topping: Place chocolate and copha in a large heatproof mixing bowl. Place the bowl over a saucepan of simmering water; making sure the base of bowl does not touch the water. When the chocolate mixture has melted, remove from heat and stir until smooth. Pour over the set caramel filling. Chill in the refrigerator for at least 4 hours or overnight.

5. When cold and set, remove slice from the tin, peel off lining paper and cut into 24 squares of 5cm x 5cm each. To make cutting easier, use a knife that has been dipped in hot water and wiped dry.