For the cake:

80g (3oz) butter, softened (I used lightly salted. If you use unsalted add 1/4 tsp salt)

280g (10oz) caster (superfine) sugar

240g (8.5oz) plain (all-purpose) flour

1 tbsp baking powder

240ml (8.5 fl oz) whole milk

1/2 tsp vanilla essence

2 large eggs

397g (14 oz) tin dulce de leche or caramel (I used Carnation)

For the icing:

85g (3 oz) plain chocolate (I used 50% cocoa solids)

285g (10oz) icing (confectioner’s) sugar

1.5 tbsp cocoa powder

340g (12 oz) butter, at room temperature

1 tsp vanilla extract

120ml (4 fl oz) double cream

2 full size Mars bars (Milky way bars in the US)