Billionaire Bars (Caramel Slice)

Butter Cookie Base

1/2 cup white sugar
2 Tbs brown sugar

Pinch of salt
2 1/4 cups plain flour
250g unsalted butter

Filling

125g unsalted butter, cut into chunks
1/2 cup brown sugar
1 (400ml) can sweetened condensed milk
1 tsp vanilla

Topping

2 cups (350g) dark chocolate chips

1/2 cup (90g) white chocolate chips

Soften butter and add it to all the dry ingredients for the base. Mix ingredients until it holds together like a dough. Press into lined and greased baking tray. Bake for 25 mins at 160C or until lightly browned. Let this cool fully.

For the filling, heat the butter, brown sugar and condensed milk over low heat in a heavy sauce pan. Let the mixture lightly simmer, and stir constantly until it thickens and becomes a medium caramel color (about 20 mins). Remove from the heat, and stir in the vanilla. Pour the filling over the cookie base, and spread evenly. Let this cool completely before adding the chocolate topping.

To make topping, melt the the chocolates separately (using a double boiler).  Spread dark chocolate over caramel and drop spoonfuls of white chocolate on top. Lightly drag lines of melted chocolate all over the top to create a marbled effect. Let the bars sit in the refrigerator, until the chocolate becomes firm. Allow them to sit at room temperature before cutting to avoid chocolate cracking.