200g plain flour
75g caster sugar
25g soft brown sugar
1 large tin condensed milk
200g milk chocolate
9in square cake tin lined with parchment paper
Preheat the oven to 170C/340F/ gas 3
To make the base
Rub the butter into the flour, add the sugar and stir to combine.
Press into the cake tin and bake for 35 minutes until golden brown
Remove from the oven and allow to cool
For the filling
Place all the filling ingredients in a sauce pan and stir constantly over a moderate heat until it begins to simmer. Continue stirring until it thickens, this should take a few minutes.
Spread over the base and allow to cool completely.
For the topping
Melt the chocolate in a bowl over a pan of simmering water and spread it over the filling.
Cool completely and cut into squares.