Burnt butter caramel slice

Thanks to this recipe from Cook Republic.

Biscuit base

1 cup plain flour

1/2 cup desiccated coconut

1/2 cup brown sugar

125g butter, melted

Mix together, pour into lined lamington tin and bake until golden. 

Caramel topping

1/3 cup golden syrup

125g butter, melted

1 400g can sweetened condensed milk

Stir together over low heat for about 5-7 minutes (caramel will be smooth and thickened).

Pour caramel over biscuit based and put in oven for 25 mins at 180 degrees - or until caramel is browning in spots (my oven was at least 25 minutes).  Cool for a couple of hours before serving.  Attempt not to eat all at once. 

As you can see, it's a simple recipe, so it just calls out for modifications - what about adding nuts?  I am going to try one batch with salted peanuts and another with unsalted macadamias, will report back.